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FAQs2021-05-08T06:54:48+00:00
What is a tungsten steel cutting knife?2021-06-21T02:10:49+00:00

Tungsten steel carton board cutting knifeTungsten steel knife, also known as tungsten carbide cutting knife or tungsten carbide slitting knifeAnchor icon, includes tungsten steel carton board cutting knife, cutting machine blade, V-CUT blade, slitting blade, CNC blade, cutting machine blade, widely used for slitting paper, plastic films, cloth, foam, rubber, copper foils, alumium foils, graphites and so on.

What material is used for tungsten steel slitting cutter?

The slitter knife is made of tungsten carbide materials, but other materials are available. Such as HSS, 9CrSi, Cr12Mo, VW6Mo5, Cr4V2,hard alloy, etc.

What is the prospect of the market for precision wire drawing dies?2021-06-21T01:32:11+00:00

Wire drawing dieAnchor icon is an important tool for drawing all kinds of metal wire. The quality of wire drawing die directly affects the quality of wire, and the life of wire drawing die affects the wire drawing output and production efficiency.

Therefore, to improve the quality of drawing die and prolong its life is the content of drawing die manufacturers’ continuous research. The quality of wire drawing die is related to life and material, pass design, manufacturing process, die making equipment and testing instruments.

Factory Long Working Life PCD Wire Drawing Die for Alloy Wire
UKO company overview

Where are the main producers of wire drawing dies in China?

According to the latest data provided by the cemented carbide branch of China Tungsten Industry Association, in 2020, there will be 500 cemented carbide production enterprises in China, most of which are mainly concentrated in the producing areas of tungsten mines, such as Hunan Province, Jiangxi Province and Guizhou Province.

The main products of Zhuzhou UKO precision carbide Co., Ltd.Anchor icon are: polycrystalline diamond drawing dies, special drawing die, wire and cable extrusion die, cemented carbide (tungsten steel) standard parts and other more than 1800 varieties, which are widely used in automobile parts, non-ferrous metal processing, steel, hardware, military industry, aerospace and other fields, Therefore, in the drawing die manufacturers, product technology and design strength is very good.

UKO is equipped with various equipment for manufacturing and testing molds, supplemented by more than 60 professional and technical personnel and mold manufacturing personnel with rich practical experience. As long as users provide product drawings or samples, they can provide customers with high-precision molds in a short time.

What are the manufacturing process of drawing die?

  1. Diamond nesting process: This is an important link in the production process of wire drawing die, and the inlay process directly affects the seed quality of wire drawing die. At present, there are two ways to insert the diamond drawing dies: one is hot insert, the other is powder insert.
  2. Cemented carbide insert sleeve: the interference method is used to insert the sleeve, which has a reinforcing effect on the outside to ensure that the die blank does not break.
  • The function of drawing die drilling technology is: to adapt to the requirements of different types of drawing machine, easy to operate, and for diamond, drawing dies drilling, laser drilling is currently used at home and abroad. The difference is that most manufacturers in China can only drill holes without diameter change, or laser drilling technology can be used. The hole shape is obtained by grinding, and the production efficiency is low, Mold quality and accuracy is not high enough; Forming holes as shown in Fig.
  • Grinding process is an important part in the production of drawing die, which is quite different. It is divided into three steps: rough grinding, fine grinding and polishing. The grinding level at home and abroad is the same. In foreign countries, it is completed by ultrasonic grinding machine. Under the strong vibration of ultrasonic grinding machine and the grinding effect of diamond powder, the drawing die is shaped into a standard shape. Polishing is also done by ultrasonic grinding machine, but diamond powder and its operation method are slightly different from rough grinding process.
Structure of the wire drawing dies core

Many domestic manufacturers use mechanical grinding method, the traditional R series arc mold, mostly using turning grinding needle, with grinding paste as abrasive. Because the hardness of the grinding needle is far lower than that of the abrasive and the die hole, the shape and size of the grinding needle are easy to change. In order to ensure the consistency of the hole shape, the grinding needle must be changed frequently. After the introduction of linear pass, the original grinding needle no longer meets the requirements, and the grinding needle of new material must be used.

For example, the diamond powder is plated on the surface of the grinding needle by the buried sand electroplating process, which greatly prolongs the service life of the grinding needle and creates the necessary conditions for machining the die hole meeting the standard requirements. However, this kind of grinding needle must be used on the high-speed grinding machine (that is, the cutting speed is not less than 36m / s) to meet the working conditions of the diamond and prevent carbonization. For the small hole drawing die, the fine grinding needle is easy to bend and deform, so the new technology of ultrasonic grinding must be adopted.

How to develop and improve the drawing die manufacturing process?

At present, many wire drawing die manufacturers in China still use the former Soviet Union, Eastern Europe and other countries’ mold making theory and technology from 1950s to 1960s. This “habit” no longer meets the needs of modern high-speed wire drawing, so we must improve the quality of wire drawing die as soon as possible

  • Learn the linear pass theory of modern drawing die;
  • Should have advanced technology manufacturers, learn other people’s full set of molding technology, out of the shackles of traditional theory and experience;
  • Introduce foreign advanced mold making equipment to narrow the gap with foreign mold making equipment, so as to achieve high precision and high quality of mold;
  • Improve the porosity of Synthetic Polycrystalline Diamond. The quality of China’s polycrystalline diamond is quite different from that of foreign similar products. The surface roughness of drawing die made of China’s polycrystalline mold is high, which should be changed from the process;
  • China has issued the new standard of “hard alloy die blank for wire, rod and tube drawing die”, so far there is no unified standard for polycrystalline diamond die, and a unified industry standard should be formulated.

In addition, for a long time, there is no special research institution in China to research and promote modern mold making theory and new technology, so the spread range and speed of theory and technology are affected. In view of the main factors affecting the quality of wire drawing die in our country, if the above aspects are improved, the wire drawing die made in our country will be able to meet the needs of high speed wire drawing.

What are router bits for woodworking?2021-06-18T08:09:55+00:00

Woodworking router bitsAnchor icon ( milling cutter ) is a rotary cutter with one or more cutting edges, which is mainly used for woodworking milling processing. When the cutter body rotates, the machined object does not rotate, and the cutter teeth intermittently cut off the redundant wood in turn, similar to metal cutting milling cutter.

Do you know the production techniques of tungsten steel milling cutters?
Router bits structure

Structure of woodworking milling cutter

  • Chip evacuation groove: the groove of the milling head is a deep spiral groove running along with the cutter, while the sharp blade along the edge of the groove is called the blade. The cutting edge cuts the material, and the chip of the material pushes the chip discharge slot through the rotating drill bit. Each chip chute has almost always had a blade, but some cutters have two blades per chip chute. Generally, the chip chute and blade can be used interchangeably. Milling cutters may have one to more blades, and two, three, and four are the most common. Usually, the more teeth the blade has, it can remove the material faster. Therefore, the 4-tooth cutter can cut materials at twice the speed of the 2-tooth cutter.
  • Helix angle: the groove of the milling cutter is almost always spiral. If the chip chute is straight, the entire blade will immediately impact the material, causing vibration, reducing accuracy and surface quality. The chip discharge slot can be set at a certain angle to make the blade gradually enter the material and reduce the vibration. Usually, the finishing tool has a higher spiral angle to get better machining.
  • Router bits handle: a handle is a cylindrical (non-groove) part of a tool that is used to secure and position it in the tool holder. The handle can be completely circular and held by friction or may have a welding plane, where the set screw is also called a headless screw that contacts without tool sliding to increase torque. The diameter may be different from the diameter of the cutting part of the tool, so it can be maintained by a standard tool clamp.

What are the types of woodworking router bits?

According to processing purposes, wood milling cutter can be further divided into:

  • Straight knife: slotting
  • Bottom cleaning knife: slotting and bottom cleaning
  • Trimming knife: straighten the edge
  • Fillet cutter: rounding edge
  • End milling cutter: machining groove and step surface
  • Saw blade milling cutter: processing deep groove and cutting workpiece
  • Minzai knife: trimming round edge
  • Round bottom knife: round groove
  • 90 ° V-knife: open V-groove and straight plate folding
  • 45 ° Bevel knife: 45 ° hypotenuse
  • Horse nose thread knife: repair 60 ° Or 30 ° hypotenuse
  • Two arc nail clipper: drawer handle
  • Keyhole knife: open the frame hole and hang it on the nail
  • T-knife: cutting side groove or milling T-groove
  • Dovetail knife: board joint.
  • Square tooth tenon cutter: floor splicing
  • Fillet tenon cutter: door panel tenon
Types of woodworking router bits

Parameter description of woodworking router bits

Although there are many types of router bits, it is important to understand the chip formation for using them. When the router bits rotates, the material to be cut is fed into it, and each tooth of the cutter cuts off a small piece of material. The size of the piece depends on several variables:

Name Description
Surface cutting speed (VC) This is the speed at which each blade passes through the material as the tool rotates. This should not be confused with the feed rate. This value is also known as tangential velocity.
Spindle speed (S) This is the tool speed, measured in revolutions per minute (RPM). The typical value is hundreds of RPM, up to tens of thousands of RPM.
Tool diameter (D): The diameter of the cylindrical part of the tool.
Feed per tooth (Fz): This is the distance the material is fed into the tool as each tooth rotates. This value is the size of the deepest cut of the cutter teeth.
Feed rate (F): This is the rate at which the material is fed into the tool.
Cutting depth: This is the depth of the tool under the surface of the material to be cut. This will be the height of chip production. Generally, the cutting depth will be less than or equal to the diameter of the cutting tool.
Number of teeth (z): That is the number of milling cutter teeth.

Calculation formula of woodworking router bits

Usually, we need to know three parameters: spindle speed (S), feed rate (F) and cutting depth to decide how to select cutting materials.

Spindle speed Feed speed
S=1000Vc/πD F=zSFz
From the formula of spindle speed s, it can be seen that larger tools need lower spindle speed, while smaller tools may run at high speed. The formula of feed rate f shows that increasing S or z can provide higher feed rate. So you can choose the tool with the highest number of blades, which can still handle the cutting load.

What are the processing methods of woodworking router bits?

There are two processing methods of woodworking router bits: forward milling and reverse milling. Router bits can cut in two directions, sometimes called reverse or up, forward or down.

Reverse milling with woodworking router bits Reverse milling: the cutting thickness starts from zero and increases to the maximum. At the beginning of cutting, the cutter does not cut, but slides over the material surface until the cutter teeth suddenly bite and start cutting. This will deform the material (point a in the figure) and blunt the tool, leaving a bad surface on the material
Forward milling with woodworking router bits Forward milling: each blade joins the material at a certain position, and the cutting width decreases from the maximum to zero. The chip is set behind the cutter, which makes it easier to remove the chip. The blade does not rub against the material, so the tool life may be longer. However, climbing can impose a large load on the machine, but it is not recommended for older milling machines or machines.

How to choose woodworking router bits?

Choose the right woodworking tools, pay attention to a cost-effective. Milling cutters on the market can be divided into three grades: ordinary, high-quality and high-grade.

Some of the ordinary milling cutters are packed very ordinary. You can see that they are ordinary. There is another kind of ordinary milling cutter with paint and a transparent shell. This kind of milling cutter looks like a boutique. Its essence is ordinary. You should be careful when choosing it. Some of the high-quality milling cutters are packed simply, while others are packed fancy. The sharpness of the blade is the main factor for this kind of cutters. Generally speaking, the brighter the blade is, the finer the workmanship is. High-grade milling cutter is reliable in quality but expensive.

Generally speaking, ordinary milling cutter is used for low-density and low hardness plates. Plates with nails have a high loss of milling cutter. Ordinary milling cutter is used for few plates. Good milling cutter is used for high-density and high hardness plates. Good milling cutter is used for acrylic plate and artificial stone.

5 Ways to increase the life of circular slitting blades in 20212021-06-16T13:51:22+00:00

3.25diameter circular knife blade part number 5012Circular Slitter KnivesAnchor icon can be used as a cutting food tool in the process of use, so how to do for the service life of the cutter blade to continue to improve? The general method is to improve the ability of cutting machine blades to resist mechanical abrasion and the ability of cutting blade anti-corrosion wear. Now we need to know more about it together. The cutter blade is mainly used for the cutting of paper, tape, tape, film, gold, silver, copper, aluminum, jig alloy foil and other articles. The cutter blade is in circular shape. Generally, the circular blade is used in mechanical equipment, mainly cutting, trimming and other processing functions. The circular blade usually has a middle hole, which is designed to fix it on the mechanical equipment, thus achieving the cutting function. There are also many round blades with teeth (flat teeth, sharp teeth, irregular teeth), and the cutting edge has three types: double-sided, single-sided and non-cutting edge.

  • Surface heat treatment: through proper surface heat treatment technology, the development and transformation of the organization management structure of Chinese metals can be made, the surface hardness of cutter blade can be improved and the wear resistance can be increased. The circular blade forms a circular shape outside, and generally, it is used in mechanical equipment, mainly cutting, trimming and other processing functions. The circular blade usually has a middle hole, which is designed to fix it on the mechanical equipment, thus achieving the cutting function. There are also many round blades with teeth (flat teeth, sharp teeth, irregular teeth), and the cutting edge has three types: double-sided, single-sided and non-cutting edge.
  • Layer technology: layer technology is a chemical heat treatment method to change the chemical composition of cutter blade surface and improve the wear resistance and corrosion resistance of cutter blade.
  • Plating technology: electroplating is a traditional Chinese method of protection research. The adaptability of electroplating is very strong, and it is not affected by the size and batch of workpiece. It can be electroplated on iron base, non-iron base, powder metallurgy parts, plastics and graphite.
  • Thermal spraying technology: thermal spraying technology is a method of heating metal, alloy, cermet, oxide, carbide and other spraying materials to melting or semi melting state by using gas, liquid fuel or arc and plasma arc as heat source. The solid surface layer is atomized, sprayed and deposited by high-speed airflow on the surface of the workpiece.
  • Coating technology: coating treatment technology is a kind of material and surface chemical modification research technology developed in China in the early 1970s. It can be applied a thin layer of refractory element gold (or non-metallic) compound with high wear resistance on the cutter blade structure base by our certain method to improve the durability, corrosion resistance and high-temperature oxidation resistance of the cutter blade.

The above five methods can improve the service life of the cutter blade. If you want to improve the service life of your cutter blade, try it.

Do you know the production techniques of tungsten steel milling cutters?2021-06-03T09:14:35+00:00

Tungsten steel milling cutter is a kind of cutter made of tungsten steel (cemented carbide, also known as tungsten titanium alloy). Generally, it is mainly used in CNC machining center and CNC engraving machine.

It can also be installed on ordinary milling machine to process some relatively hard and uncomplicated heat treatment materials. Tungsten steel milling cutter is widely used and high-speed machining is used. The hardness of tungsten steel milling cutter is Vickers 10K, second only to diamond. Because of this, tungsten steel milling cutter is not easy to be worn, and it is brittle and hard, not afraid of annealing.

Do you know the production techniques of tungsten steel milling cutters?

Characteristic

Cemented carbide tools (especially indexable cemented carbide toolsAnchor icon) are the leading products of CNC machining tools. In some countries, more than 90% of turning tools and 55% of milling tools are made of cemented carbide, and this trend is increasing. Since the 1980s, the tool industry has been expanding the production of all kinds of integral and indexable cemented carbide tools or inserts, and their varieties have been extended to all kinds of cutting tools. The indexable cemented carbide tools have been expanded from simple turning tools and face milling tools to all kinds of precision, complex and forming tools. Cemented carbide is also a common material for making drill, face milling cutters and other general cutting tools. At the same time, the use of cemented carbide in reamer, end mill, medium and large modulus gear cutter and broach is increasing. The annual output value of cemented carbide tools and inserts has accounted for more than 30% of the total output value of cutting tools.

Classification

According to the grain size, cemented carbide can be divided into ordinary cemented carbide, fine grain cemented carbide and ultra-fine grain cemented carbide. According to the main chemical composition, cemented carbide can be divided into tungsten carbide based cemented carbide and titanium carbide based cemented carbide. Tungsten carbide based cemented carbides include tungsten cobalt (YG), tungsten cobalt titanium (YT) and rare carbide (YW). They have their own advantages and disadvantages. The main components are tungsten carbide (WC), titanium carbide (TIC), niobium carbide (NBC) and so on. The common bonding phase is Co. Titanium carbide based cemented carbide is a kind of cemented carbide with tic as the main component, and the commonly used metal bonding phases are mo and Ni.

The processing technology and parameter design of tungsten steel milling cutter are quite different from that of common structural steel.

Drilling processing:

Due to the poor thermal conductivity and small elastic modulus of stainless steel, it is difficult to process the hole. Tungsten steel milling cutter to solve the problem of hole processing of this kind of material is mainly to select the appropriate tungsten steel tool material.

Boring process:

  • Tool material selection: due to the large cutting force and high cutting temperature when machining stainless steel parts, the tool material should be tungsten steel with high strength and good thermal conductivity.
  • Tungsten steel milling cutter can be used to process quenched parts of this kind of material, which has high wear resistance. Compared with diamond, its outstanding advantage is that its heat resistance is much higher than that of diamond, and it can withstand very high cutting temperature.
  • Tool geometry parameters: tool geometry parameters play an important role in its cutting performance. In order to make cutting light and smooth, tungsten steel milling cutter should adopt larger rake angle to improve tool life. Generally, the rake angle is 10°~20° in rough machining and 15°~20° in semi finish machining; Take 20°~30° for finishing. The selection of main deflection angle is based on 30°~45° when the rigidity of process system is good; If the rigidity of the process system is poor, take 60°~75°, when the ratio of workpiece length to diameter exceeds 10 times, take 90°.
  • The cutting edge of tungsten steel milling cutter should be kept sharp, so as to reduce work hardening. The feed and back feed should not be too small, so as to prevent tungsten steel milling cutter from cutting in the hardened layer and affecting the service life of the cutter.
  • Attention should be paid to the grinding of the chip-breaking groove. Because the stainless steel chips are strong and tough, the grinding of the chip breaking groove on the front face of the tungsten steel milling cutter should be appropriate, so that the cutting process can be easily interrupted, contained and removed.
  • The selection of cutting parameters is based on the characteristics of materials. Low speed and high feed rate are suitable for cutting.
  • The selection of cutting fluid should be appropriate. Because of tungsten steel, it is very important to select cutting fluid with good adhesion resistance and heat dissipation in boring of tungsten steel milling cutter, such as cutting fluid with high chlorine content, and water solution without mineral oil and sulfite with good cooling, cleaning, rust prevention and lubrication.
What are the characteristics of stainless steel milling cutters?2021-06-03T06:24:42+00:00

What are the problems in stainless steel milling?

  • First of all, the coolant will make the chips cool too fast and fuse on the blade, which will reduce the tool life.
  • Too high feed rate will cause the accumulation of materials, and too low feed rate will cause friction between the tool and the workpiece, which will also lead to overheating.
  • In fact, in order to avoid tool bumps, machining stainless steel cutting heat is necessary. When machining stainless steel milling cutterAnchor icon, proper cutting speed should be selected to make the chip light brown.
  • If the chip turns dark brown, the cutting speed has reached the maximum. It is necessary to pay attention to the cutting speed of the milling cutter when machining stainless steel.
What are the characteristics of stainless steel milling cutters

What should be paid attention to when milling stainless steel?

  • Cutting tools should be rigid, advanced, and have as high overload capacity as possible. It is better to cut under 75% of the load calibration capacity of the machine tool.
  • The workpiece and cutter should be clamped firmly, the extension of cutter should be as short as possible, and additional support can be used when necessary. Whether it is high-speed steel tools or cemented carbide tools, they should be kept sharp at all times. It is better to sharpen them regularly, and do not sharpen them when they have to.
  • Good performance lubricants, such as chlorinated petroleum grease, should be used. This lubricant is particularly effective for heavy cutting where the feed rate is rather slow.
  • For high-speed finishing cutting, kerosene is recommended to dilute the lubricant before use. This mixture can keep the workpiece and tool at a low temperature. Special attention should be paid to the cutting of Cr Ni austenitic stainless steel. When cutting this kind of stainless steel, we should be careful as far as possible, and may carry out compulsory cutting to avoid pause, so as not to cause work hardening and material slipping.

How to choose the milling cutter for stainless steel milling?

The characteristics of milling stainless steel are: the adhesion and fusibility of stainless steel are strong, and the chips are easy to adhere to the cutter teeth, which worsens the cutting conditions; In reverse milling, the cutter teeth slide on the hardened surface first, which increases the trend of work hardening; When milling, the impact and vibration are large, which makes the cutter teeth easy to crack and wear.

In addition to the end milling cutter and some end milling cutters which can be made of cemented carbide, other kinds of milling cutters are made of high-speed steel, especially tungsten molybdenum series and high vanadium high-speed steel, which have a good effect. The tool life can be 1-2 times higher than that of W18Cr4V. Cemented carbide grades suitable for stainless steel milling cutters are YG8, YW2, 813, 798, YS2T, YS30, YS25, etc.

When milling stainless steel, the cutting edge should be sharp and able to withstand impact, and the chip groove should be large. Large helix angle milling cutter (cylindrical milling cutter, end milling cutter) can be used, and helix angle B is from 20 ° Increase to 45 °( n=5 °), The tool life can be increased by more than 2 times, because the working rake angle G0e of the milling cutter is changed from 11 ° Increased to 27 ° Above, milling is light and fast. But b value should not be larger, especially when B ≤ 35 ° To avoid weakening the cutter teeth.

When machining stainless steel pipe or thin-walled parts with wave edge end mill, the cutting speed is light, the vibration is small, the chip is fragile and the workpiece is not deformed. High-speed milling with carbide end milling cutter and indexable end milling cutter can achieve good results in stainless steel milling.

Milling parameter cases

SWC end mill milling 1Cr18Ni9Ti, its geometric parameter is GF = 5 °、 gp=15 °、 af=15 °、 ap=5 °、 kr=55 °、 k′r=35 °、 g01=-30 °、 4 mm, re = 6 mm, when VC = 50 ~ 90 m / min, VF = 630 ~ 750 mm / min, a ′ Pb can reach 20 = 2 ~ 6 mm, milling power is reduced by 44%, efficiency is also greatly improved. The principle is to grind the negative chamfering on the main cutting edge. During milling, the chip build-up is artificially generated to replace the cutting edge for cutting. The rake angle of the chip build-up is ~ 302. Due to the effect of the main deflection angle, the chip build-up is caused by the thrust parallel to the cutting edge generated on a rake face and becomes the secondary chip outflow, which takes away the cutting heat and reduces the cutting temperature.

When milling stainless steel, it is necessary to use the parallel milling method as far as possible. Asymmetric milling method can ensure that the cutting edge smoothly cuts away from the metal, the chip bonding contact area is small, and it is easy to be thrown off under the action of high-speed centrifugal force, so as to avoid the phenomenon of chip spalling and edge collapse when the cutter teeth re cut into the workpiece, and improve the tool durability.

The effect of spray cooling is the most significant, which can increase the durability of milling cutter more than one time. If the general 10% emulsion is used for cooling, the cutting fluid flow should be ensured to achieve sufficient cooling. When milling stainless steel with carbide milling cutter, VC = 70-150 M / min and VF = 37.5-150 mm / min should be selected. At the same time, appropriate adjustment should be made according to different alloy grades and workpiece materials.

What are the factors controlling the wire drawing process?2021-06-03T03:08:04+00:00

Drawing dies processingIn metal processing, using external force to let carbon steel, stainless steel, aluminum, copper and other metals forced through the drawing diesAnchor icon, the cross-section is compressed into the required shape and size, this is our common drawing process.

Drawing process can be divided into dry drawing and wet drawing according to the different equipment and lubricants used. Common problems and solutions in wet drawing:

  • First of all, the selection of wet drawing process is generally aimed at small diameter, or surface finish, or metal drawing with special requirements of subsequent processing technology.
  • The main types of wet drawing lubricants are pure oil, synthetic oil, emulsion, paste, etc.
  • The selection of wet drawing lubricant is mainly based on the comprehensive consideration of raw material, mold, surface quality and downstream application.
  • For example, for stainless steel drawing, pure oil with high viscosity and special extreme pressure additives is generally selected; for carbon steel, emulsion is generally selected; for non-ferrous metals, pure oil or synthetic oil or emulsion can be selected according to the final application requirements. There are special requirements, you can also choose paste.

What problems will appear in the process of metal wire drawing?

Generally speaking, in the actual operation, whether dry drawing or wet drawing process, there will be a variety of problems. Let’s take a look at the common problems in the process of wet drawing and the corresponding solutions:

  • Discoloration of wire: The surface discoloration of wire (such as copper) is mainly oxidation discoloration, which is caused by improper temperature Drawing dies machineand humidity conditions. It may be that the concentration of emulsion is too low or the temperature is abnormal; Too much oil is attached to the wire; The water quality is unqualified; Mixing of foreign oil products, etc. To find out the reason of its discoloration, we can take corresponding measures according to the actual situation. For example, if the concentration of emulsion is too low, it will be raised to the normal standard; If the temperature is abnormal, it should be adjusted to 35 ℃~45 ℃; Check whether there is wire drawing oil overflow at the outlet; Remove the foreign oil mixed in the emulsion.
  • The wear of die is big: One of the reasons leading to large die loss is the improper operation of the machine, the other is the wrong choice of lubricant. If the machine does not work properly, the operator needs to practice continuously and check its working condition before each operation. In addition, lubricant plays a key role in assisting and promoting wire drawing process, and its selection is very important. At present, drawing products from contat are highly praised by many enterprises. On the one hand, it has a complete range of products, covering all drawing applications; On the other hand, viafil? Representative lubricant, with the advantages of fast drawing speed, good chemical compatibility, not easy to break wire and so on, can extend the service life of the mold. Not only that, Condat can also customize lubrication solutions, leading the wire drawing industry.
  • Broken wire, scratch and burr: Wire breakage, scratch and burr greatly affect the appearance and quality of products. The causes of these problems may be the contamination of metal chips, the blockage of die hole or the aging of lubricant caused by the direct contact between metal and die due to insufficient lubrication. These problems can be solved by filtering equipment to remove metal chips, remove the blockage and replace the lubricant.
  • Emulsion delamination / excessive surface precipitates: The invasion of microorganisms, low pH, ultra-high hardness and inorganic salt of water for liquid preparation, high temperature of emulsion may cause emulsion stratification or excessive precipitation on the surface of wire rod, and the solutions should be targeted. If it is the invasion of microorganisms, fungicides can be added, and sodium hydroxide solution or triethylamine alcohol can be added; If pH is too low, sodium hydroxide solution or triethylamine alcohol should be added; When the hardness and inorganic salt of the water for liquid preparation are too high, the water for liquid preparation needs to be replaced; The temperature of emulsion is too high, it needs to be cooled moderately before use.
What is CBN tools?2021-06-03T02:02:53+00:00

Boron nitrideCBN (cubic boron nitride)Anchor icon was first synthesized by General Electric (GE) Company in the 1950s under high temperature and high pressure by manual method. Its hardness is second only to diamond but much higher than other materials. Therefore, CBN and diamond are collectively referred to as superhard materials.

Cubic boron nitride (CBN) polycrystalline sintered body is mainly prepared by sintering CBN powder and a small amount of binders (such as CO, Al, Ti and tin) at the pressure of 4000-8000 MPa and temperature of 1300-1900 ℃;

The polycrystalline sintered body with cemented carbide substrate was prepared by sintering the cubic boron nitride powder and binder as a layer and cemented carbide (sheet or powder) as a layer under the above pressure and temperature;

At the same time, the original physical and chemical properties of CBN can be maintained, and the disc with diameter up to 16mm can be made. After being cut into proper shape, CBN can be used as the tool head of turning toolAnchor icon and boring tool, which is suitable for cutting hardened steel, cast iron and nickel alloy.

CBN is a kind of material whose hardness is second only to diamond (diamond), so CBN blade belongs to superhard material tool. Because CBN can withstand the high temperature of 1300~1500 ℃, CBN blade can carry out high-speed cutting of ferrous metals at high temperature without chemical reaction, with high machining accuracy, low surface roughness and cutting life 5-10 times longer than cemented carbide tool.

CBN tools have been widely used in many metal cutting industries because of their excellent properties such as high thermal hardness, high wear resistance and not easy to stick.

The application scope mainly includes the following difficult to machine materials:

  • All kinds of quenched steel, such as carbon tool steel, alloy steel, bearing steel, die steel, high speed steel, etc
  • Thermal spraying materials, such as Ni based and Fe based products
  • Wear resistant cast iron: such as V-Ti Cast Iron, high phosphorus cast iron and chilled cast iron, etc
  • Titanium alloy and heat resistant alloy parts
CBN Tools
What is a carbide tap?2021-06-03T01:17:15+00:00

Introduction

The utility model relates to a cutter for processing internal thread, which is provided with a groove along the axial direction. It’s also called a screw tap. Taps are

Carbide Tap

divided into straight groove taps, spiral groove taps and spiral point taps (tip taps) according to their shapes.

The straight groove tap is easy to process, with low precision and high output. It is generally used for thread processing of ordinary lathe, drilling machine and tapping machine, with slow cutting speed. Spiral groove taps are mostly used for drilling blind holes in CNC machining centers, with fast processing speed, high precision, good chip removal and good alignment. There is a chip holding groove in the front of the screw tap, which is used to process through holes.

Most of the taps provided by the tool factory are coated taps, which greatly improves the service life and cutting performance compared with uncoated taps. The cutting load distribution of taps with unequal diameter design is reasonable, the machining quality is high, but the manufacturing cost is also high. Trapezoidal thread taps often adopt unequal diameter design.

Component

Machine and hand taps are standard taps for cutting common threads. Chinese tool manufacturersAnchor icon usually call high-speed steel grinding tap as machine tap, and carbon tool steel or alloy tool steel rolling (or cutting) tap as hand tap. In fact, their structure and working principle are basically the same. Generally, the tap is composed of working part and handle. The working part is divided into cutting part and calibration part. The former is grinded with cutting cone to undertake cutting work, while the latter is used to calibrate the size and shape of thread.

Purpose

It is used for processing common internal thread of nut or other machine parts (tapping). Machine tap usually refers to high speed steel grinding tap, which is suitable for tapping on machine tool; Hand tap refers to carbon tool steel or alloy tool steel rolling (or incisor) tap, suitable for manual tapping.

Tap is a kind of cutting tool for processing various medium and small size internal threads. It has simple structure and is easy to use. It can be operated by hand or on machine tools. It is widely used in production.

For small internal thread, tap is almost the only tool. The types of taps are: hand taps, machine taps, nut taps, extrusion Taps, etc.

Tapping is a relatively difficult processing procedure, because the tap is almost buried in the workpiece for cutting, the processing load of each tooth is greater than other tools, and the tap along the thread and the workpiece contact surface is very large, when cutting the thread, it must contain and remove chips, therefore, it can be said that the tap works under very bad conditions. In order to make the tapping work smoothly, all kinds of problems should be considered in advance. Such as the performance of the workpiece material, what kind of tool and machine tool to choose, how high cutting speed to choose, feed rate, etc.

Tapping on special workpiece materials

The machinability of workpiece material is the key to tapping. Now the main concern of tap manufacturers is to develop taps for special material processing. According to the properties of these materials, the geometry of the cutting part of the tap is changed, especially its rake angle and the amount of dent (hook) – the degree of dent in the front.

The maximum processing speed is sometimes limited by the performance of the machine tool. For smaller taps, the spindle speed may have exceeded the maximum spindle speed in order to reach the ideal speed [RPM = (sfm x 3.8) / tap diameter].

On the other hand, high speed cutting with a larger tap will produce a larger torque, which may be greater than the horsepower provided by the machine tool. The cutting speed can reach 250 SFM with 700 psi internal cooling tool. On the other hand, the cutting speed of the machine tool without internal cooling facilities can only reach 150 SFM. The tap is different from most metal cutting tools, because it has a very large contact area with the hole wall of the workpiece, so cooling is very important.

If the high-speed steel tap overheats, the tap will break and burn. The geometric characteristics of Noris high-performance tap are large back angle and inverted tap.

The service life of the taps can be greatly improved by the geometric shape of the taps mentioned above combined with special coating surfaces (such as tin, TiCN, CrN or TiAlN). These heat-resistant, smooth coatings reduce the cutting force and allow tapping at higher cutting speeds. In fact, the development of new high-performance taps has greatly improved the speed and power of machine tool spindle.

Carbide tap

As cemented carbide toolsAnchor icon gradually replace high-speed steel tools in turning, cemented carbide taps are more and more used in threaded hole processing. Compared with high-speed steel, cemented carbide has high hardness and brittleness. Tapping with cemented carbide taps has the problem of chip treatment. However, cemented carbide tap for processing cast iron and aluminum alloy materials, its use effect is very good, the main form of tap damage is mechanical wear.

As the automobile industry processes a large number of cast iron and aluminum alloy parts, cemented carbide taps are used to obtain long tool life. When machining workpieces of these materials, the service life of cemented carbide taps is longer than that of high speed steel taps.

In the automotive industry, the reduction of tool change time is an important factor, and the long life of cemented carbide wire will minimize the tool change time. The effect is very good when the surface coated carbide tap with small helix angle is used to tap the aluminum alloy workpiece with silicon content of 8% – 12%.

The taps made of submicron grain cemented carbide can increase the toughness of the cutting tool without reducing its hardness, which is very effective in cutting hardened steel, plastics and difficult to machine nickel base alloy.

The dl15ni series nickel alloy special taps produced by Noris company can continuously tap more than 200 screw holes on Inconel 718 under certain conditions, which can only be achieved by regrinding before.

Characteristic

Taps are usually divided into single or group taps. Small and medium sized through hole threads can be tapped with a single tap at one time. When processing blind holes or large-size screw holes, group taps are commonly used, that is, more than two taps are used to complete the processing of one screw hole in turn. There are two kinds of design of group taps: equal diameter and unequal diameter. For taps of equal diameter design, only the length of each tap is different; For the taps with unequal diameter design, the sizes of each thread are different, and only the last one has complete tooth profile.

Tap classification

  • According to different driving: hand tap and machine tap
  • According to the processing method: cutting tap and extrusion tap
  • According to the processed thread: metric coarse tap, metric fine tap, pipe thread tap, etc
  • According to its shape, it can be divided into straight groove tap, spiral groove tap and spiral point tap
  • According to the tapping direction of tap, it can be divided into parallel tap and reverse tap

Tap type

  • Straight groove tap: The straight groove tap has the best versatility and the strongest rigidity. Therefore, generally in the processing of materials with higher hardness (such as: quenched steel above 40HRC) and chips with powder particles (such as cast iron and cast aluminum), straight groove taps are preferred.
  • Spiral groove tap: Spiral groove taps are more suitable for processing through-hole threads (also known as blind holes), and the chips are discharged upward during processing. Because of the helix angle, the actual cutting rake angle of the tap will increase with the increase of the helix angle. Experience tells us: for materials with high hardness, the helix angle should be selected smaller, generally around 30 degrees, so as to ensure its own rigidity and prolong the life of tap. When processing non-ferrous metals, such as copper, aluminum, magnesium and zinc, which are not very hard, the helix angle should be larger, which can be about 45 degrees. The cutting is sharper, which is conducive to chip removal.
  • Edge angle tap: When machining thread, the chip is discharged forward, and the edge angle tap is preferred for through-hole thread. Because its design is based on the straight groove tap, and then use the grinding wheel to cut a cut obliquely at the edge, so its own rigidity can be comparable to the straight groove tap.
  • Extrusion tap: Different from the first three types of cutting taps, the extrusion taps are processed through the plastic deformation of the material itself, and the internal thread shape is extruded in the bottom hole by extrusion. Therefore, the processing material should not be too hard. The advantage of this method is that it does not produce chips, so 90% of the machining problems can be eliminated. However, due to extrusion molding, there is a small groove on the top of the processed internal thread, so it is not suitable for the work with higher sealing requirements.

How to use tap?

  • When tapping, first insert the tap to make the tap center line consistent with the drilling centerline.
  • Rotate the two hands evenly and add a little pressure to make the tap feed, and there is no need to add pressure after feed.
  • Each time the tap is turned, it reverses about 45 ° To cut off the chips to avoid blocking.
  • If the tap is difficult to rotate, do not increase the rotating force, otherwise, the tap will break.

How to choose taps?

Thread is the most common method to connect mechanical parts, and tap is the most commonly used tool to process internal thread. Proper selection of taps for internal thread processing can ensure the quality of thread connection and improve the service life of taps.

Select tap tolerance zone

All domestic machine taps are marked with pitch diameter tolerance zone Codes: H1, H2 and H3 respectively indicate the same position of tolerance zone, but the tolerance values are different.

The tolerance zone code of hand tap is H4, the tolerance value, pitch and angle error are larger than machine tap, and the material, heat treatment and production process are not as good as machine tap. H4 may not be marked according to regulations.

The grade of tolerance zone of internal thread that can be processed by pitch diameter tolerance zone of tap is as follows: the code of tolerance zone of tap is applicable to the grade of tolerance zone of internal thread

H1 4H、5H
H2 5G、6H
H3 6G、7H、7G
H4 6H、7H

Some enterprises use imported taps. German manufacturers often mark them as iso14h, iso26h and iso36g (international standard iso1-3 is equivalent to national standard h1-3). In this way, the code of tolerance zone of taps and the tolerance zone of Machinable internal threads are marked.

How to choose the standard of tap thread?

There are three common systems of common thread: metric system, English system and unified system (also known as American system). Metric system is a thread with 60-degree tooth angle in mm. For example: m8x1-6h represents the tolerance zone of 8 mm diameter metric fine thread, 1 mm pitch and 6h internal thread.

Inch system is a thread with 55-degree tooth angle in inches. For example: BSW 1 / 4-20 means 1 / 4-inch diameter, coarse pitch 20 teeth per inch, this thread is rarely used. Another unified system is in inches, tooth angle of 60 degrees of thread.

The diameter is less than 1 / 4 inch, which is usually indicated by numbers. From No. 0 to No. 12, the diameter specifications are 0.06 inch to 1 / 4 inch respectively. The United States still mainly uses unified thread.

What is the code meaning of CNC milling inserts?2021-06-02T04:23:55+00:00

If you are engaged in NC machining, are you not clear about the key number code on the cutter box when you use the CNC bladeAnchor icon; Are you worried about how to choose the right type of blade in the face of many blades? If you have such problems at present, please watch the following content, which will be helpful to you. Because, in the complex world of metal cutting, correct metal cutting means that the first need to understand the workpiece material, and then choose the correct blade groove shape and grade to adapt to specific applications, so as to get twice the result with half the effort!

What is the code meaning of cnc milling inserts?

cutting tools parametersIn the article “how to distinguish the material grades of workpieces in numerical control processing technology”, I explained the characteristics and applicable occasions of the material grades of workpieces (P, m, K, N, s, H). On the toolbox plate in the figure below, P indicates that this type of blade is suitable for cutting steel. The two-digit data not exceeding 50 after P indicates the tool performance, from high wear resistance to high toughness. The performance of p10-p30 in this figure is moderate. In addition, the reference cutting parameters suitable for this tool are also marked. You can understand the above.

So what does CNMG120404-PM on the cutter box plate mean? This is the focus of this paper. Next, mainly explain the meaning of the model. After mastering the basic knowledge of cutting tools, you only need a picture to completely master the rules of blade coding! In the process of NC turning, the workpiece material has a direct impact on tool wear. For example: in steel processing, the main problems are flank wear, crater wear and plastic deformation; In the process of stainless steel processing, the main problems are chip accumulation and groove wear; In cast iron machining, the main problems are flank wear and plastic deformation, which is very necessary for tool selection.

Therefore, the selection of the blade should be based on the material type and application of the workpiece, but also on the shape of the blade. The tip angle of the blade should be from the minimum 35° Change to round blade, as shown in the figure below, and each shape of blade has different characteristics, how to select? Look down.

Blade Shape Blade Shape R Blade Shape S Blade Shape C Blade Shape W Blade Shape T Blade Shape D Blade Shape V
ISO(the first character) R S C W T D V
Cutting tools parameters

CNMG blade parameterThe larger the tip angle, such as R, means the greater the strength of the blade and the higher the feed rate, but it will increase the cutting force and vibration, which is suitable for rough machining, hard material machining and discontinuous machining;

The smaller the tip angle, such as V, means that the cutting edge strength is worse, but it has better accessibility in profiling, which can reduce the cutting force and vibration, and is suitable for finishing, profiling, longitudinal turning, etc.

After mastering the above knowledge, you can master the tool coding rules and understand the meaning of cnmg120404-pm by looking at the figure below.

Now you can understand the meaning of this blade code! If you find it useful, please pay attention to it and collect it!

What is the high-temperature alloy KCS10B tool material?2021-05-28T08:27:06+00:00

KCS10B can be used in all kinds of the most common turning toolAnchor icon shapes, sizes and chip breaking groove types. It can be used to cut nickel, cobalt, iron base and other superalloys in aerospace and other fields.

KCS10B has a revolutionary coating, which is attached to the ultra-fine grained cemented carbide substrate. Its coating adhesion is very excellent. When machining superalloy, the tool life can be extended by up to 50%, and it can provide more stable and controllable processing process and higher productivity.

KCS10B overcomes the two most common wear modes in turning superalloys: Crater wear and deep cutting wear, which often lead to unexpected or even catastrophic tool failure.

Material of kcs10b turning tool

KCS10B has a revolutionary coating, which is attached to the ultra-fine grained cemented carbide substrate. Its coating adhesion is very excellent. When machining superalloy, the tool life can be extended by up to 50%, and it can provide more stable and controllable processing process and higher productivity. Kcs10b overcomes the two most common wear modes in turning superalloy: crater wear and deep cut wear, which often lead to unexpected or even catastrophic tool failure.

Special sputtering process

  • The key to the success of kcs10b is the high power pulsed magnetron sputtering (high PIMS). In the traditional PVD coating process, small raindrops like AlTiN will fall on the tool.
  • The high power meter PIMS produces not small raindrops, but a fine layer of AlTiN fog, which falls on the tool to form a series of extremely thin, smooth and wear-resistant coatings.

Less wear

High-temperature alloys such as Inconel 718 and WCCo 31 are a headache due to rapid tool wear and unpredictable tool life. Kcs10b has been proven to reduce deep cut wear and extend tool life from 3 minutes to more than 5 minutes in roughing applications. Tool life in finishing applications performs better, with visible crater wear and subsequent tool failures typically delayed two or three times compared to competitors.

The positive and negative inserts, as well as various chip forming, edge treatment and chip breaking groove types, make kcs10b an ideal solution for turning iron-based (S1), cobalt-based (S2) or nickel-based (S3) superalloys.

KCS10B tool life reference

Chromium nickel-iron alloy 718 (NiCr19FeNbMo-DIN), 36-39 HRC, continuous turning, external cooling; Cutting parameters: 61m / min (200sfm), 0,25 mm / RPM (0.0096 IPR), 1,5 mm doc (0.06 IPR).

Due to the super-smooth coating and special edge treatment of KCS10B, the deep cutting wear and crater wear are easier to control; In addition to smoother surfaces, the new coating process allows us to create sharper blades.

The advanced honing and edge treatment process reduces the friction that causes heating, thus further improving the tool life, which also means less chip buildup, which is another common failure mode in superalloy materials.

What are the advantages of woodworking spiral cutter head?2021-05-28T07:18:28+00:00

With the development of science and technology, the discarded spiral head for woodworkingAnchor icon has gradually replaced the traditional flat knife, four side planer, and in the near future, the discarded spiral head will be gradually popularized in the woodworking machinery industry. As an innovative product of flat knife and four side planer, the design of discarded spiral cutter head has become the standard tool for woodworking machinery in Europe and America.

The discarding spiral cutter head distributes the planing points to each processing blade more scientifically, and finely adjusts the angle between the blade and the processing surface, which can be easily adjusted to adapt to the processing of different materials.

Advantages:

  • Spiral cutting surface: high precision design and manufacturing technology, the discarded blades are reasonably arranged around the cutter body to form a smaller cutting surface in unit time, so as to improve the blade burning mark and the berm.
  • Fast heat dissipation speed: some cutter bodies are made of 7 Series aerospace-grade aluminum alloy, which not only improves the heat dissipation speed but also improves the stability and structural strength of the cutter body, thus improving the service life of the cutter body.
  • Discarded blade: the imported Luxemburg small blade is adopted, and the assembly method without high-temperature welding ensures that the original hardness of each blade is above hra93.5 degrees, which greatly improves the service life of the tool. When the blade is passivated, the factory operator can remove the blade by himself, which is easy to operate and saves time.
  • Long service life: the service life of the aluminum alloy cutter body is 1-2 times longer than that of the ordinary flat cutter, and 3-4 times longer than that of the double-face planer and the four-face planer.
  • Sawdust is very small: the sawdust formed by a spiral cutting in unit time is very small, so it is easy to discharge the sawdust from the processed wood surface in the Sino British dust collection system.
  • Low noise: the noise value generated by contacting the wood surface in unit time and contacting the wood surface in the same time with the flat knife will be reduced by 30 to 50dB.
  • Discard type spiral cutter head is divided into: heavy cutting spiral cutter head and light cutting spiral cutter head. Heavy cutting spiral cutter head is mainly used for automatic copying milling machine, vertical shaft machine, four side planer, cutting molding. The light-cutting spiral cutter head is mainly used for vertical shaft machine, four side planer, etc., and the main cutting plane is smooth and round.

How to replace an ordinary planer with a spiral cutter shaft?

  • Check whether the original bearing meets the accuracy requirements, and it is recommended to replace the new bearing. The bearings to be replaced shall be P5-grade bearings with low noise and high precision.
  • Check the inner diameter of the bearing pedestal (the inner bore of the bearing has been worn out for many years, which will cause a lot of noise and damage the bearing in a short time, and make the bearing go to the inner or outer circle). If there is a problem with the bearing pedestal, it must be replaced with a new one.
  • Check and clean the shaft head and seat before installing the bearing; Add 3 × white grease into the bearing; When installing the bearing, it is required to press the bearing in smoothly and evenly (if there is hydraulic equipment, please use hydraulic equipment to install the bearing, if there is no hydraulic equipment, steel sleeve should be used to contact the inner ring of the bearing to knock in evenly, so as to avoid damaging the outer circle of the shaft head by knocking on one side).
  • There are four cutting-edge surfaces. If one cutting edge of the blade is blunt, it is necessary to tighten the screw anticlockwise to clean the tool holder and blade. It is recommended to use gasoline or Tianna water to clean it easily; When changing the cutting edge, we must pay attention to: each blade has a mark on the surface, and we must ensure the uniform orientation, so as to avoid uneven wood cutting surface caused by the wrong replacement of the new and old cutting edge.
  • If the screw is too tight or rusty, it is difficult to loosen it. First, put the bit into the plum blossom mouth of the screw, and tap it gently with a small hammer (pay attention not to damage the blade), and then it is easy to loosen it with a wrench; To avoid the phenomenon that the screw is rusty and hard to loosen when changing the blade next time, it is recommended that the screw hole must be cleaned every time when changing the blade, and then the screw can be dipped with oil and then screwed into the screw hole so that the screw can be easily loosened when changing the blade next time.
How to calculate CNC tool radius compensation?2021-05-28T04:41:56+00:00

The concept of tool compensation (offset) in CNC machining center is widely used in our life. For example, when driving a car around a stone, the driver will let the car go around the stone on the side of the stone.

Considering that the car has a certain width, the driver should keep the center line of the car at least half the width of the car away from the stone. In the 1960s and 1970s, there was no concept of compensation in NC machining, so programmers had to program around the relative relationship between the theoretical route and the actual route of the tool, which was easy to make mistakes. The concept of compensation has greatly improved the efficiency of programming.

Principle of CNC tool compensation

There are three kinds of compensation in NC machining: tool radius compensation, tool length compensation and fixture compensation. This paper mainly introduces the principle of tool radius compensation:
CNC tool radius compensation

  • Purpose of tool radius compensation. When contour machining is carried out on the milling machine because the milling cutterAnchor icon has a certain radius, the tool center (tool center) path does not coincide with the workpiece contour. If the numerical control device does not have the function of tool radius automatic compensation, it can only program according to the tool center path (dotted line in Fig. 1). Sometimes its numerical calculation is quite complex, especially when the tool diameter changes due to tool wear, regrinding and tool replacement, it is necessary to recalculate the tool center path and modify the program, which is cumbersome and difficult to ensure the machining accuracy. When the CNC system has the function of tool radius compensation, the programming only needs to be carried out according to the contour line of the workpiece (thick solid line in Fig. 2). The CNC system will automatically calculate the tool center path coordinates to make the tool deviate from the contour of the workpiece by a radius value, that is, radius compensation.
  • Method of tool radius compensation. CNC tool radius compensation is that the process of tool center path is executed by CNC system. When programming, it is assumed that the radius of the tool is zero, and programming is carried out directly according to the contour shape of the part, while the actual tool radius is stored in a programmable tool radius offset register, The NC system automatically calculates the tool center path according to the part program and tool radius to complete the machining of the part. When the tool radius changes, there is no need to modify the part program, just modify the radius value stored in the tool radius offset register or select the tool corresponding to the tool radius in another tool radius offset register.
How to distinguish between cold rolled steel bars and hot rolled steel bars?2021-05-28T03:39:05+00:00

Cold rolled ribbed steel barThe difference between hot rolled steel bar and cold rolled steel bar: the difference between them is not only the difference between hot and cold but also the strength, yield point, tensile strength and so on. Let’s have a look.

  • Hot rolled steel bar is a kind of finished steel bar formed by hot rolling and natural cooling. It is made of low carbon steel and ordinary alloy steel under high temperatures. It is mainly used for reinforcement of reinforced concrete and prestressed concrete structures. It is one of the most widely used steel products in civil engineering. Generally, the steel bars with a diameter of 6.5-9 mm are mostly rolled into coils;  The diameter of 10-40mm is usually 6-12M long. Hot rolled steel bars are directly processed on the steel mold in the steel furnace in the steel processing plant, that is, the hot (so called “hot rolling”) products come out of the furnace and can be used after cooling.
  • Cold rolled steel bars are produced by cold mill rollsAnchor icon processing of hot rolled steel bars, such as cold drawing and drawing of steel bars at room temperature. The yield strength of the hot-rolled steel bar is low and its plasticity is good. Cold rolled steel bars have higher yield strength and poor plasticity, and their ultimate tensile and compressive strength are the same.
  • How can we tell which is hot rolled and which is cold rolled at a glance? The initials of hot rolled steel bars are “H”, such as HRB335 and hrb40 with hot rolled ribs, and the initials of cold-rolled steel bars are “C”, such as crb550 and crb650 with cold-rolled ribs. It is easy to distinguish the beginning letters of hot-rolled and cold-rolled steel bars by remembering them.
What is a carbide ball and what are its uses?2021-05-28T02:55:16+00:00

Cemented carbide ballAnchor icon, also known as tungsten steel ball, refers to the ball and ball made of cemented carbide. Cemented carbide ball has high hardness, wear resistance, corrosion resistance, bending resistance, and bad service environment. It can replace all steel ball products. Commonly known as tungsten steel ball, it refers to the ball and ball made of cemented carbide. Cemented carbide ball has high hardness, wear resistance, corrosion resistance, bending resistance, and bad service environment, which can replace all steel ball products.

Cemented carbide balls are widely used in high-end industries, such as precision bearing, instrument, instrument, pen making, spraying machine, water pump, mechanical accessories, sealing valve, brake pump, punching and extruding hole, oil field, hydrochloric acid laboratory, hardness measuring instrument, fishing gear, counterweight, decoration, finishing and so on.

Tungsten carbide ball

Component

Carbide ball is a kind of powder metallurgy product which is sintered in vacuum furnace or hydrogen reduction furnace with high hardness refractory metal carbide (WC, TIC) micron powder as the main component and cobalt (CO) or nickel (Ni), molybdenum (MO) as the binder. The common cemented carbide includes YG, YN, YT, YW series.

Classification

Cemented carbide balls mainly include blank ball, fine grinding ball, punching ball, bearing ball, valve ball, non-magnetic ball, Monel ball, through-hole ball, metering ball, scraping ball and pen ball.

Grade

YG6 cemented carbide ball, YG6X cemented carbide ball, YG8 cemented carbide ball, yg13 cemented carbide ball, YG20 cemented carbide ball, yn6 cemented carbide ball, yn9 cemented carbide ball, yn12 cemented carbide ball, YT5 cemented carbide ball and YT15 cemented carbide ball.

Characteristic

Cemented carbide ball has high hardness, wear resistance, corrosion resistance, bending resistance and bad service environment. It can replace all steel ball products. The hardness of cemented carbide ball is more than 90.5, and the density is 14.9g/cm3.

What tool is used for turning carbide roll rings?2021-05-26T06:31:01+00:00

What is mill rolls?

Mill rolls are the main consuming part of the rolling mill. According to material, it can be divided into cast alloy steel rolls, high-speed steel (HSS) rolls, high carbon high-speed steel rolls and tungsten carbide rolls, etc. especially for large roll, it is difficult to machine because of its high hardness, uneven allowance and irregular surface, The bn-k1 grade of non-metallic binder cubic boron nitride tool effectively solves the problem of difficult machining of casting roller.

Tungsten carbide rolls youtube video

Characteristics and heat treatment process of roller
In the rolling mill of iron and steel plant, the pressure produced by rolling a pair or group of rollers is used to roll the steel. As the roll needs to bear the dynamic and static load, wear and temperature change during rolling, the following characteristics should be ensured for the roll:

  • High hardness
  • Good wear resistance
  • Good impact resistance and hot cracking resistance

The heat treatment process of roll:

  1. The roll needs to be annealed before rough machining to eliminate the internal stress;
  2. After rough machining, quenching and tempering are carried out to improve the surface hardness of the roll and obtain good performance.

After heat treatment, the hardness of the roller is generally higher than hrc45, some even as high as HRC60, which is difficult to process.

How to select tool material for turning casting roll?

As the roll belongs to the casting molding, the tool material selected in the processing is very important, which requires not only high hardness, strength, good wear resistance, but also good impact resistance. Cemented carbide toolsAnchor icon (such as YG6 and YG6X) are recommended for casting rolls below hrc45;

Cubic boron nitride tools

For casting rolls above hrc45, it is recommended to use ceramic tools and cubic boron nitride tools. Ceramic tools are only suitable for the finishing process due to their brittleness. Traditional cubic boron nitride tools are also suitable for the finishing process. However, the bn-k1 brand of Valin superhard cubic boron nitride tools is different. They can not only rough the surface of casting rolls but also process with large allowance, Intermittent processing does not break the knife.

Bn-k1 belongs to the non-metallic adhesive cubic boron nitride tool. On the basis of ensuring the hardness and wear resistance of the traditional cubic boron nitride tool, it improves the impact resistance of bn-k1. It can be rough and finish machining, saving the processing cost and improving the processing efficiency.

Models of common turning tools and blades

  • Model selection of common clamping tools for roll turning: Heavy roll lathe is often used for large roll processing, and 40 * 40 tool square of tool holder is commonly used for the heavy roll; The commonly used tool holder angle is 45 degrees, and the tool holder angle is 45 degrees. Some small rolls also use 25 * 25 and 32 * 32 clamping tool handles. The main deflection angle of the tool holder is selected according to the “length diameter ratio” of the roll. The slender roll is usually processed with a 90-degrees or 75-degree tool, while the thick roll is usually processed with 45 degrees or arc tool.
  • The model of cubic boron nitride blade is selected according to the cutting allowance and processing condition of turning roll: when bn-k1 cubic boron nitride blade is used to process cast iron roll, rnmn200800, rnun200800, rnmn150700, rnun160800, rnun150716 and rnmn150716 are generally used. Among them, bn-k1 grade is selected for alloy cast iron and chilled cast iron, and bn-s20 grade is selected for casting high speed steel. Bn-s20 grade is also a non-metallic adhesive cubic boron nitride tool, which has better impact resistance and is suitable for processing cast steel / forged steel parts. Bn-k1 grade is mainly used for processing cast iron parts, and rough and finish processing of the above two kinds of tool grades are OK.
Case study of bn-k1 grade CBN tool for machining cast iron roll
Workpiece material Hardness Grade Processing method Cutting parameters Processing effect
High nickel chromium alloy cast iron roll HSD80 BN-K1 Dry cutting AP = 4mm, FR = 1mm, VC = 55m / min Compared with the European and American brand ceramic blade: on the basis of feed rate 2 times higher than the ceramic tool, the single blade life is 6 times of the ceramic blade.
Grinding method of hard alloy taper shank end mill2021-05-24T08:21:00+00:00

What is taper shank end mills?

Taper shank end mills, also known as Morse taper shank end mills, range in size from 6 mm to 100 mm. It consists of blade and Morse taper shank. The cutter is used to rough machining plane, step, groove and vertical plane. The number of teeth is small and the space of chip holding is large, which is suitable for rough machining.

Taper shank end mills

Milling features:

  • High productivity milling cutter continuous rotation, and allows a higher milling speed, so it has higher productivity.
  • In intermittent cutting milling, every cutter tooth is cutting intermittently, especially in end milling, the milling force fluctuates greatly, so the vibration is inevitable. When the vibration frequency is the same as or multiple to the natural frequency of the machine tool, the vibration is the most serious. In addition, when high-speed milling, the cutter teeth have to undergo periodic cold and thermal shock, which is prone to crack and chipping so that the tool life is reduced.
  • Multi-Tool and multi-edge cutting milling cutter has many teeth and the total length of the cutting edge is large, which is beneficial to improve the tool life and productivity. But there are also two problems as follows: first, the cutter teeth are prone to radial runout, which will cause unequal load and uneven wear of cutter teeth and affect the quality of a machined surface; Second, the chip space of the cutter teeth must be enough, otherwise the cutter teeth will be damaged.
  • Different milling methods, according to different processing conditions, in order to improve tool life and productivity, different milling methods can be selected, such as reverse milling, forward milling, symmetric milling and asymmetric milling.
What is a meltblown die?2021-05-24T06:44:18+00:00

As we all know, the melt-blown cloth is the “heart” of masks, so melt-blown cloth mold is also used to produce melt-blown cloth mold, also known as melt-blown cloth nozzle or spinneret in the industry.

Melt blown cloth mold is made of yk30 (SK3) carbon tool steel, tungsten carbideAnchor icon, and other steel. For the die head of melt-blown cloth, the micro-hole diameter is very small, mostly 0.1-0.3mm, with a spacing of 0.6-0.7mm. For example, a 550mm die has nearly 1000 holes, and the perpendicularity of 0.2mm is the key. Laser drilling has high precision.

Design drawing of melt blown fabric

Design drawing of melt blown fabric

Most of the die heads are rectangular spinnerets, which are made of SUS316L, SUS304, SUS630, SUS431 and other stainless steel.

In the past, in order to ensure the concentricity of spinneret micro-hole and pilot hole, it was generally processed from one side, from macropore to micropore. Because of the great overhanging depth, the difficulty coefficient is very high. Due to the urgent need of rapid production, most of the process has been changed to micro-hole processing from the back, but this will produce concentricity, burr and other problems.

After using YFG abrasive flow to solve the problems of burr and hole plugging, polishing and cleaning can be carried out, and the machine can be put into use. In the production of melt-blown fabric, the wire is sprayed through the spinneret of melt-blown fabric mold. Meltblown fabric is the core material of the mask. Polypropylene is the main raw material of the melt-blown fabric. The fiber diameter can reach 1-5 microns.

In the spinneret module, there is a row of spinning micropores under the spinning melt pool, and the diameter of micropores is generally 0.3-0.4 mm. In order to be more conducive to spinning forming, the aspect ratio is much larger than that of conventional melt spinning, which is generally 10-15. At the same time, a special air cavity is formed between the spinneret assembly and the air knife. The high-pressure hot air flows through the narrow slot of the air cavity at a speed similar to the speed of sound. A spinning tap is formed between the blade of the air knife and the tip of the spinneret assembly.

The melt is ejected from the spinning micropores and is clamped by high-speed airflow at the spinning cone, and then stretched to form ultrafine fibers after cooling.

What is the use of tungsten carbide roller ring?2021-05-24T04:56:43+00:00

The roller is made of WC and CO by powder metallurgy. There are two types of WC roller: integral type and combined type (see cemented carbide roller sleeve). It was born with the development of metal processing industry after the advent of powder metallurgy technology in 1909.

Since the introduction of carbide drawing die in Germany in 1918, the research of cemented carbide in various countries has been stimulated, and rollers for various purposes have appeared one after another. However, the wide application of WC roller was after 1960. In 1964, the first high-speed non twist wire rod mill of Morgen company was born, which increased the finishing speed of wire rod four times at that time.

Because the finishing mill works under high speed and high stress, the wear resistance of cast iron roll and tool steel roll is poor, the service life of rolling groove is short, the repair and loading and unloading of roll are very frequent, which affects the efficiency of the mill and can not meet the requirements of finishing production. Therefore, it is replaced by combined tungsten carbide roll. There are more than 200 sets of Morgan mills in the world, which consume hundreds of tons of WC rolls annually.

Tungsten carbide cold rollers

Figure 1
WC rollers struture

Figure 2

In the 1980s, tungsten carbide rolls developed in China have been successfully applied to high-speed wire rod mills. Ch series rolls of General Iron and Steel Research Institute of Ministry of metallurgy and YGH series rolls of Zhuzhou 601 plant have been mass-produced.

The composition, microstructure and properties of WC rolls vary with the working conditions of the rolls. Even for the same finishing mill, the composition of the rolls in different stands is different. The high-speed wire rod mill roll is mainly made of tungsten carbide with cobalt as a binder. Due to the poor water quality, a few continuous casting and rolling mills also use tungsten carbide rollers with Co-Ni Cr as binders, so the cost is low.

The morphology of the WC roll is shown in figure 1. The properties of the rolls with two common components are shown in the table. The metallographic structure is composed of matrix phase WC and binder phase Co, as shown in Figure 2: white phase is WC, black phase is Co. It can be seen from the table that the hardness of carbide roll increases with the increase of WC content; The toughness increases with the increase of binder content.

The application characteristics are shown in the table. The hardness of the WC roller is high, and its hardness value changes little with temperature. The hardness value at 700℃ is four times that of high-speed steel; The elastic modulus, compressive strength, bending strength and thermal conductivity of the tool steel are more than one time higher than those of the tool steel. All these properties ensure that the wear resistance and deformation resistance of WC roll are much better than that of tool steel roll in the working process, so as to ensure the smoothness of roll groove and the constancy of size, which is very important to ensure the surface quality and dimensional accuracy of wire rod.

T.C roller chemical composition & properties of grade
Grade Wc Content Co Content TRS Density Hardness
% % N/mm² G/Cm³ HRA
YG15 85 15 ≥2020 13.9-14.1 ≥86
YGH30 85 15 ≥2700 14.02 ≥84.9
UKO's PDF Download

Due to the high thermal conductivity of WC roll, the heat dissipation effect is good, the time of high temperature on the roll surface is short, so the high-temperature reaction time of the roll with harmful impurities in the cooling water is short. Therefore, WC roller is more resistant to corrosion and thermal fatigue than tool steel roller.

Production method tungsten carbide roll is produced by powder metallurgy method with tungsten carbide powder and cobalt powder (a small amount of other hard phases or alloy elements can also be added) as raw materials. The above two kinds of powders were wet ground and mixed by ball mill. After mixing, drying and sieving, the mixture become the intermediate product cemented carbide mixture. The mixture is pressed and sintered into roll blank. After grinding, polishing or re-grooving, the roll blank can be used for production.

The quality standards and influencing factors of WC roller are: material porosity, WC grain size, total carbon and free carbon content, density, hardness, magnetic saturation strength, coercive force, bending strength, impurity content, etc. In addition, there are the machining accuracy and surface roughness of the roll. Each index reflects the quality of the roller and indicates its performance. The influencing factors of roller quality are: dispersion, particle size and particle size distribution of WC powder and Co powder in mixture, the content of total carbon, free carbon, oxygen and iron, etc; The type and quantity of binder, the temperature and time of degumming, the temperature, time and atmosphere of sintering, etc. In addition, the precision of the grinding machine and the quality of the diamond grinding wheel affect the quality of roll.

Tungsten carbide rollerAnchor icon has been used in various fields of metal plastic processing. From non-ferrous metals to steel, from hot-rolled wire rod, pipe to cold-rolled foil, rebar and so on, tungsten carbide roller is used. China has been able to produce from φ 8~ φ There are dozens of varieties and specifications of 300 mm tungsten carbide rolls. However, with the high speed of wire rods finishing rolling (up to 130m / s), people are exploring ways to improve the hardness and strength of WC roller. This is mainly due to the addition of a small amount of TAC, NBC, Ni, Cr, Mo and other elements into the WC roll; By means of hot isostatic pressing, vacuum sintering low pressure hot isostatic pressing, heat treatment and so on, the roller with better quality can be made.

How are the ribs of cold rolled ribbed steel bars formed?2021-05-24T01:47:32+00:00

The diameter of the cold-rolled ribbed steel barAnchor icon is reduced by hot-rolled wire rods through multiple cold rollersAnchor icon. After the cold roll pressing, the internal stress is eliminated and the crescent ribbed bar with 2D or 3D is formed. Cold rolled ribbed steel bar is a new product of cold-drawn low carbon steel wire in prestressed concrete members. In cast-in-place concrete structure, it can replace grade I steel bar to save steel. It is a better kind of cold processed steel of the same kind.

Cold rolled ribbed steel bar

Technical performance

Application effect

Cold rolled ribbed steel bar is a new product of cold drawn low carbon steel wire in prestressed concrete members. In cast-in-place concrete structure, it can replace grade I steel bar to save steel. It is a better kind of cold processed steel of the same kind. Its performance and application effect are as follows

The mechanical property index of LL550 in Chinese national standard “cold rolled ribbed strip” gb13788-2000 is formulated with reference to international standard and developed country standard. The tensile strength is 550MPa and the elongation is standardized in Germany δ From the comparison of these two indexes, the standard of cold-rolled ribbed bar in China is not lower than the international standard.

Advantage

Cold rolled ribbed bars have the following advantages:

  • The steel has high strength, which can save construction steel and reduce project cost. Compared with hot-rolled plain round bar, LL550 cold-rolled ribbed bar can save 35% – 40% steel when used in cast-in-place structure (especially in roof). If we don’t use the hook, we need to save more steel. According to the market price of steel, the cost of steel can be saved about 800 yuan per ton of cold-rolled ribbed steel bar.
  • The bond anchorage performance between cold-rolled ribbed bar and concrete is good. Therefore, when it is used in the component, the phenomenon of cracking in the anchorage zone and steel wire sliding is fundamentally eliminated, and the bearing capacity and crack resistance of the end of the component are improved; In reinforced concrete structure, the crack width is smaller than that of plain round steel bar, even than that of hot rolled thread steel bar.
  • The elongation of cold-rolled ribbed bar is higher than that of the same kind of cold-rolled steel.
Sharpening of woodworking carbide insert welding tooth saw blade?2021-05-21T07:27:26+00:00

Cemented carbide is hard and brittle, so great attention should be paid in the process of transportation, installation and disassembly to avoid damaging the serrated blade and personal injury. Usually, the grinding work of the woodworking saw bladeAnchor icon is completed by the maintenance workers of the buyer, but it is very important to know the necessary knowledge.

Woodworking saw blade corresponding to the front angle Type of saw blade Universal saw Electronic cutting saw Single stroke Double stroke Solid wood saw Solid wood slitting saw Solid wood cross-cutting saw Slotting saw
Front angleα 12 15 0 12 18 15 15 15

When does woodworking saw blade need sharpening?

  • If the sawing quality does not meet the requirements, such as burr or roughness on the surface of the product, it needs to be sharpened immediately.
  • When the alloy edge is worn to 0.2mm, it must be ground.
  • Push material hard, paste time.
  • Abnormal noise.
  • When cutting, the saw blade has the phenomenon of sticking teeth, dropping teeth and chipping teeth.
Remove gum and impurities

How to sharpen woodworking circular saw blade?

  • The grinding is based on grinding the back of the tooth, and the front of the tooth is paved. There is no special requirement on the side of the tooth.
  • After grinding, the condition that the front and back angles remain unchanged is that the angle between the working face of the grinding wheel and the front and rear tooth surfaces to be grinded is equal to the grinding angle, and the distance that the grinding wheel moves is equal to the grinding amount. To make the working surface of the grinding wheel parallel to the serrated surface to be ground, and then gently contact, and then make the working surface of the grinding wheel away from the tooth surface, then adjust the working surface angle of the grinding wheel according to the grinding angle, and finally make the working surface of the grinding wheel contact with the tooth surface.
  • The grinding depth is 0.01-0.05 mm in rough grinding; The feed rate is suggested to be 1-2 m/min.
  • Manual fine grinding of serrations: after a small amount of wear and chipping on the tooth edge and grinding the serrations with silicon chloride sand wheel, if it is still necessary to grind the serrations, hand grinder can be used to fine grind the serrations to make the tooth edge sharper. In fine grinding, the force should be uniform, and the working face of the grinding tool should be kept parallel when the grinding tool moves back and forth. The grinding amount should be consistent to ensure that all tooth tips are in the same plane.

Front angle grinding

Front angle grinding

Rear angle grinding

Rear angle grinding

Comparison of grinding durability of woodworking saw blade

Comparison of grinding durability of woodworking saw blade

What is used to sharpen woodworking saw blades?

A professional automatic grinding and sawing machine, resin CBN grinding wheel, manual grinding and sawing machine and universal grinding machine.

Precautions

  • Before grinding, remove the resin, debris and other debris stuck on the saw blade.
  • The original geometric design angle of the saw blade should be strictly followed to avoid damage to the tool caused by improper grinding. After grinding, it can be put into use only after passing the inspection, so as to avoid personal injury.
  • If manual grinding equipment is used, it is necessary to have an accurate limit device and detect the tooth surface and tooth top of the saw blade.
  • Special coolants should be used for lubrication and cooling during grinding, otherwise, the service life of the tool will be reduced, and even the alloy tool head will have an internal crack, which will lead to dangerous situations.

In a word, the grinding process of cemented carbide saw blade is different from that of the ordinary circular saw blade. When the grinding rate is high, the grinding heat is high, which not only makes the cemented carbide crack but also has poor grinding quality. Through reasonable grinding and use, the service life of the saw blade can be greatly extended (generally about 30 times of regrinding), the requirements of processing technology can be better met, the manufacturing cost can be effectively reduced, and the production efficiency can be improved.

What is a keyway cutter?2021-05-21T03:27:12+00:00

Keyway milling cutterKeyway milling cutter is a kind of milling tool, and its edge diameter limit error is divided into E8 and D8. Keyway milling cutter has a small helix angle (20 degrees), groove depth, approximately straight back folding, and is similar to twist drill.

Content

  • Difference
  • Grinding
  • Tool setting device

Difference:

  • Keyway milling cutter can not process plane, while end milling cutter can process plane.
  • Keyway milling cutter is mainly used for processing keyway and groove. Keyway milling cutter is good at keyway milling. For example, the end milling cutter of 6mm is easier to break than the keyway milling cutter of 6mm, and the keyway milling cutter can complete the task smoothly.
  • The cutting amount of the keyway milling cutter is larger than that of the end milling cutter.

Grind:

The width of motor shaft extension keyway “F” (its tolerance is JZ) is generally not easy to guarantee. When machining keyway on end milling machine with standard straight shank keyway cutter, it is easy to exceed tolerance requirement from upper limit. Therefore, our factory uses the method of grinding the circular edge of the knife to meet the requirements of the processing keyway. The specific measures are as follows:

  • The milling cutterAnchor icon is installed on the end milling machine to adjust the longitudinal run out of the milling cutter edge to the spindle centerline to within 0.02mm.
  • Install a piece of cast iron (HT15-33) on the worktable, mill a cylindrical hole with depth of H + 3mm (H is the depth of keyway) on the cast iron with end milling cutter at the speed of 350-450 rpm, and then withdraw the milling cutter to remove the impurities in the hole.
  • Inject proper amount of kerosene and a little 200 mesh silicon carbide grinding material into the hole, adjust it into paste shape, and at the same time, apply a little grinding material on the circumference of the milling cutter.
  • The spindle of the milling cutter is reversed, the rotation speed is 200 rpm, and the depth of the milling cutter inserted into the hole is H + 2 mm.

Tool setting device

When machining the keyway with symmetry less than 0.1 on the shaft, the workpiece can be installed on the universal milling machine with three-jaw chuck and tail thimble. The tool setting device is accurate and fast.

The length of the cylindrical rod is the same as that of the workpiece to be processed. During the operation of the cylindrical rod, first polish it, then check the parallelism between the rod and the worktable, and then press the fixture, then press the vertical support against the rod, press the measuring head of the dial indicator on the highest edge of the milling cutter side, lock the locking screw and the base screw, record the reading of the dial indicator, and then move the tool setting device to the highest edge on the other side of the rod, Check whether the dial indicator reading is the same as above. If it is different, move the worktable until the readings on both sides are the same.

With the above method, as long as the movable gauge holder is swung to make the measuring head of the dial gauge press on the side of the keyway of the workpiece, the symmetry of the working keyway can also be directly measured. The practice in the past two years has proved that this method is effective.

How is rebar made?2021-05-20T08:32:14+00:00

Steel bar is a common building material, among which threaded steel is more commonly used in the building. Its scientific name is called cold-rolled ribbed steel. It is a bar that rolls round steel on the cold rolling mill and passes the cold rollerAnchor icon to form a regular section shape, which can improve its strength and adhesion with concrete.

The economic benefit is increased after the reinforcement is strengthened by cold working. But the yield strength of cold processed steel bar is relatively large, and the safety reserve is small. So what grade of steel is a cold-rolled ribbed steel bar, and what are its advantages?

Cold rolled ribbed steel bar has many advantages in our use. Its steel strength is high, which can save construction steel and reduce project cost. It can save about 40% steel when used in the cast-in-place structure; It can eliminate the phenomenon of the anchorage zone cracking and steel wire sliding, and improve the bearing capacity and crack resistance of the end of the component; The cold-rolled ribbed steel bar is elastic and not easy to bend when pouring concrete, which provides convenience for construction

Tungsten Carbide Cold Forming Rolls for Drawing Metal Sheets

Advantages of cold rolled ribbed bar:

Cold rolled ribbed steel bar is a new type of cold rolled ribbed steel bar developed in recent years. Its production process increases the process of tempering heat treatment, has obvious yield point, and the strength and elongation indexes are significantly improved.

  • The steel has high strength, which can save construction steel and reduce project cost. Compared with hot-rolled plain round bar, LL550 cold-rolled ribbed bar can save 35% – 40% steel when used in cast-in-place structure (especially in roof).
  • The bond anchorage performance between cold-rolled ribbed bar and concrete is good. Therefore, when it is used in the component, the phenomenon of cracking in the anchorage zone and steel wire sliding is fundamentally eliminated, and the bearing capacity and crack resistance of the end of the component are improved; In reinforced concrete structure, the crack width is smaller than that of plain round steel bar, even than that of hot rolled thread steel bar.
  • The elongation of cold-rolled ribbed bar is higher than that of the same kind of cold-rolled steel.
What is carbide metal?2021-05-20T07:46:52+00:00

Tungsten carbide is a compound of tungsten and carbon. It is a black hexagonal crystal with a metallic luster, similar hardness to diamond and good conductivity.

Tungsten carbide is insoluble in water, hydrochloric acid and sulfuric acid, but easily soluble in the mixed acid of nitric acid and hydrofluoric acid. Pure tungsten carbide is fragile, if a small amount of titanium, cobalt and other metals are added, the brittleness can be reduced.

Tungsten carbide, which is used as steel cutting tool, is often added with titanium carbide, tantalum carbide or their mixture to improve the antiknock ability. The chemical properties of WC are stable. Tungsten carbide powder is used in cemented carbide production.

Cemented carbide powder

Application:

  • It is widely used in high-speed cutting toolsAnchor icon, kiln structural materials, jet engine parts, cermet materials, resistance heating elements and so on.
  • Used for manufacturing cutting tools, wear-resistant parts, melting crucible of copper, cobalt, bismuth and other metals, wear-resistant semiconductor film.
  • It can be used as superhard tool material and wear-resistant material. It can form solid solution with many carbides. WC tic co cemented carbide tools have been widely used. It can also be used as an additive for the modification of carbides in nbc-c and tac-c ternary systems. It can not only reduce the sintering temperature but also maintain excellent properties. It can be used as aerospace materials.
  • Tungsten carbide (WC) powder was synthesized from WO3 and graphite in reducing atmosphere at 1400 ~ 1600 ℃. Dense ceramic products can be prepared by hot pressing sintering or hot isostatic pressing sintering.
What are the advantages of carbide cutting tools?2021-05-20T07:23:14+00:00

Features of hard tools:

  • High hardness (86-93 HRA, 69-81 HRC);
  • Good thermal hardness (up to 900-1000 ℃, 60 HRC);
  • Good wear resistance. The cutting speed of cemented carbide tool is 4-7 times higher than that of high-speed steel, and the tool life is 5-80 times longer. The service life of the mold and measuring tool is 20-150 times longer than that of alloy tool steel. It can cut hard material about 50HRC.

Cemented carbide toolAnchor icon application: cemented carbide tool is generally used in CNC machining center, CNC engraving machine. It can also be installed on the ordinary milling machine to process some hard and uncomplicated heat treatment materials.

At present, the cutting tools for composite materials, industrial plastics, plexiglass materials and non-ferrous metal materials on the market are all cemented carbide tools.

How to detect the hardness of cemented carbide?2021-05-20T07:02:04+00:00

The cemented carbide has a series of excellent performance such as high hardness, strong toughness, wear resistance, heat resistance, corrosion resistance, high-temperature resistance, is known as “industrial teeth”, mostly used to make metal cutting toolsAnchor icon, wear parts, etc. Widely used in military, aerospace, machining, metallurgy, oil drilling, mine tools, electronic communications, construction, and other fields.

The hardness of cemented carbide is generally tested by Rockwell hardness (HRC). Rockwell hardness is an index to determine the hardness value based on the indentation plastic deformation depth, with 0.002 mm as a hardness unit. In the Rockwell hardness test, using different indenters and different test forces will produce different combinations, corresponding to different scales of Rockwell hardness. The three most commonly used scales are a, B and C, namely HRA, HRB and HRC:

  • HRA is the hardness obtained by 60kg load and diamond cone indenter, which is used for materials with higher hardness. For example steel sheet, cemented carbide.
  • HRB is the hardness obtained by using 100kg load and 1.5875mm diameter hardened steel ball, which is used for low hardness materials. For example mild steel, non-ferrous metals, annealed steel, etc.
  • HRC is the hardness obtained by 150kg load and diamond cone indenter, which is used for materials with higher hardness. For example quenched steel, cast iron, etc.

PHR Series Portable Rockwell Hardness Tester

Detection method Characteristics Tools
The hardness of cemented carbide is mainly tested by Rockwell hardness tester. PHR Series Portable Rockwell hardness tester is very suitable for testing hardness of cemented carbide. The weight precision of the instrument is the same as that of the table Rockwell hardness tester, so it is very convenient to use and carry. It belongs to non-destructive test, and the test method is relatively simple. The hardness test of cemented carbide has strong adaptability to the shape and size of the specimen, and the test efficiency is high. PHR Series Portable Rockwell hardness tester can test hard alloy workpieces with thickness or diameter less than 50 mm, hard alloy workpieces with diameter less than 2.0mm and tubular hard alloy workpieces with inner diameter less than 30mm.
How to choose cnc milling cutter fixture?2021-05-20T01:48:35+00:00

CNC milling cutter fixtureWhen using vertical milling machineAnchor icon to process some long rectangular templates, it is often necessary to use milling cutter and end milling cutter together, so frequent tool change has reduced the work efficiency, so how to achieve efficient production? This requires the use of end mill chucks.

There are two types of end mill chucks most commonly used in the market:

  • Collet with good concentricity (e.g. spring collet)
  • Side locking collet

How to choose end mill chuck?

  • Chuck with good concentricity
    Taking the spring collet as an example, the spring collet is composed of the collet body, the elastic collet inserted into the collet body and a nut which can tighten the thread on the collet. When the nut is tightened, the elastic chuck encircling the round toolholder can exert a strong clamping force on the toolholder, so the tool can obtain longer life and higher feed speed, and can improve the surface finish of the workpiece. However, this chuck has no physical stop mechanism, so it is easy to cause the bending deformation of the chuck.
  • Side locking chuck
    The side locking chuck will push the tool away from the center when clamping, so the cutting edge on one side of the milling cutterAnchor icon will bear more cutting load. Once the cutting edge is worn, the whole tool will fail in advance. However, in heavy rough milling, the fastening screw can prevent the tool from being pulled out of the chuck hole.
What is the difference between end mills and keyway mills?2021-05-20T01:44:12+00:00

Schematic diagram of milling processing

What are the differences?

  • The purpose is differentThe vertical milling cutter is used to process plane or cylindrical surface, its outer diameter is relatively loose, while keyway milling cutter is used to process keyway, its outer diameter directly affects the matching quality of keyway and keyway, so the tolerance is more strict.
  • The number of cutter teeth is differentEnd mills generally have more than three teeth, keyway mills generally have two teeth.
  • The difference of blade beltIn order to improve the working efficiency of end milling cutter, there are many edge strips. The larger the diameter is, the more the edge strips are; Keyway milling cutter generally has two edge belts, mainly for axial feed like drill bit.
  • The feed is differentThe end milling cutter can’t feed in the axial direction, it can feed in the axial direction only when it moves in the radial direction; Keyway milling cutter can be axial straight into the feed, equivalent to a drill, can drill a flat bottom hole.

How to distinguish different end mills?

  • End mills with different number and length of edgesThe number of cutting edges is selected according to the cutting mode of end mill.For example, when cutting a groove with the same cutting width and tool diameter, a larger chip holding groove is needed, and a 2-edge end mill is generally selected. In the case of side cutting with smaller cutting width, the tool rigidity should be given priority and the multi-edge end mill should be selected.Selection of blade lengthAccording to the depth of groove shape and other processing shapes, the best edge length of end mill is selected. If we pay attention to the number of regrinding and choose the end milling cutter with too long blade, it will produce chatter, which will lead to the failure to give full play to the characteristics of the end milling cutter, resulting in the difficulty to achieve high-precision finishing surface and other adverse effects.
  • End mills with different helix anglesThe larger the helix angle of the end mill, the longer the contact length between the workpiece and the cutting edge. In this way, the load on the cutting edge per unit length can be reduced, so the tool life can be prolonged. But at the same time, the cutting resistance will become larger, so it must be considered to use the tool holder with high clamping rigidity.

Types and uses of milling cutters

Category Name Application
By purpose Cylindrical milling cutter Used for machining plane on horizontal milling machine. The cutter teeth are distributed on the circumference of the milling cutter and can be divided into straight teeth and spiral teeth according to the tooth shape. According to the number of teeth, it can be divided into coarse teeth and fine teeth. The helical gear coarse tooth milling cutter has less teeth, high tooth strength and large chip space, which is suitable for rough machining, while the fine tooth milling cutter is suitable for finish machining.
Face milling cutter It is used in vertical milling machine, end face milling machine or gantry milling machine to process plane. There are cutter teeth on the end face and circumference, as well as coarse teeth and fine teeth. There are three types of structure: integral type, inlaid type and indexable type.
End mill It is used for machining groove and step surface. The cutter teeth are on the circumference and end face, and can’t feed along the axial direction when working. When the end milling cutter has an end tooth passing through the center, it can feed axially.
Three face milling cutter It is used for machining all kinds of groove and step surface. There are cutter teeth on both sides and circumference.
Angle milling cutter It is used for milling grooves with a certain angle. There are two kinds of single angle and double angle cutters.
Saw blade milling cutter It is used to process deep groove and cut off workpiece. There are many cutter teeth on the circumference. In order to reduce the friction during milling, there are 15 ‘- 1 on both sides of the cutter teeth ° The secondary deflection angle of the system. In addition, there are keyway milling cutter, dovetail groove milling cutter, T-shaped groove milling cutter and various forming milling cutters.
By structure Integral The cutter body and cutter teeth are integrated.
Integral welding tooth type The teeth are made of cemented carbide or other wear-resistant tool materials and brazed on the cutter body.
Inlaid type The cutter teeth are fixed on the cutter body by mechanical clamping. The exchangeable cutter teeth can be the cutter head of integral cutter material or the cutter head of welding cutter material. The milling cutter with the cutter head mounted on the cutter body for grinding is called internal grinding type; If the cutter head is grinded separately on the fixture, it is called external grinding.
Indexable insertsAnchor icon This structure has been widely used in face milling cutter, end milling cutter and three face edge milling cutter.

For the hard cutting materials with low heat conductivity and great influence on the heating of the blade tip, the use of large spiral angle end milling cutter is helpful to prolong the tool life. In addition, the characteristics of the finishing surface change due to the helix angle. For example, when smooth finishing is required, large helical angle end mills can be used sometimes.

However, when using the large helix angle end milling cutterAnchor icon, the cutting resistance will increase, and the force of the right spiral angle tool will also increase. Therefore, corresponding measures must be taken, such as holding the handle with high rigidity.

Although the rigidity of the tool can be ensured, sometimes small spiral angle end mills are used when the rigidity of the workpiece such as sheet metal processing is low.

Common milling cutter specification sheet

Name Material Size
Saw blade milling cutter High-Speed Steel(HSS)/Tungsten Carbide Ф60—Ф200
Incision milling cutter Ф40—Ф80
Straight tooth three-sided cutter Ф50—Ф130
Gear roller M1-M10
Straight handle keyway milling cutter Ф2—Ф20
Tapered handle milling cutter Ф14—Ф50
Vertebral swirkel trough cutter Ф14—Ф50
Where is the well known tungsten carbide manufacturer?2021-05-08T08:28:34+00:00

NO.1

Sandvik CoromantSandvik CoromantAnchor icon is the largest company of Sandvik Group with metal cutting tools as its main products. It has 73 subsidiaries or branches, 39 production bases, 3 central warehouses and 19 training centers in more than 60 countries, with a total of 7800 employees worldwide. Is the world’s leading supplier of metal cutting tools, but also tool solutions and professional processing knowledge provider.

In turning, Sandvik’s blade series covers a large number of blade types and materials, which can be used in all turning processes of different workpiece materials; In milling, it can provide unique tools for milling of various materials and types; In drilling, no matter what type of hole, it can provide high-performance bits with complete specifications for efficient production.

NO.2

ISCARIscarAnchor icon as one of the largest metal-cutting tool manufacturers in the world is one of the main subsidiaries of Berkshire Hathaway. The company was acquired by Mr. Buffett in 2006, before which it was Israel’s largest family business.

Iscar R & D, production, sales cutting, turning, milling, boring, drilling, hinge, tool handle system and other full range of tools, in aviation, steam turbine, automobile, mold, machine tools. Rich experience in providing a complete set of solutions for machine tool matching.

Ingersoll tool company of Germany, which joined Iscar, won the first milling cutter patent in the world in 1889, and initiated crankshaft turning, pulling external milling, and other machining tools. Ingersoll is also an active advocate and leader of blade vertical design.

NO.3

Seco Tools ABSECO Tools AB, one of the four largest cemented carbide tool manufacturers in the world, is listed on the Stockholm stock exchange in Sweden. Seco Tools company is a company that integrates research and development, production and sales of various kinds of carbide tools for metal processing. Its products are widely used in automobile, aerospace, generator equipment, mold, machinery manufacturing and other industries. It enjoys a global reputation and is known as the “king of milling”.

The company is famous for its series of milling and turning tools and blades. It is a professional enterprise integrating R & D, production and sales of various kinds of carbide tools for metal processing.

NO.4

KyoceraKyocera Co., Ltd.Anchor icon, formerly known as Kyoto Ceramics Co., Ltd., is a Japanese multinational company founded by Kazuo Inamori on April 1, 1959.

The mechanical tools division of Kyocera (China) Trading Co., Ltd. is responsible for selling a full range of cemented carbide and cermet blades for industrial metal machining. Cutting tools are made of ceramic, CBN, synthetic diamond and other materials. Including a variety of standard turning blades, slitting blades, cutting blades, hole lining blades, multi-functional blades, thread blades, general drilling blades, special ultra-fine micro-drilling bits, plane milling, end milling and ball head milling and other indexable blades and their supporting tool holders, Spiral Cutter Head for WoodworkingAnchor icon.

The products cover all kinds of standard and non-standard cutting tools needed in various fields such as automobile, mold processing, aerospace, rail transit, engineering machinery, energy, precision machining, etc.

NO.5

Walter companyFounded in 1919, Walter company is headquartered in Tubingen, southern Germany. So far, Walter company has 17 subsidiaries all over the world. Walter company mainly has two types of products: one is cemented carbide indexable tools, including turning, milling, drilling, expanding and boring tools and tool accessories. The other is Walter’s five-axis CNC tool grinder.

Walter company began to develop cemented carbide metal cutting toolsAnchor icon in 1926. The founder Mr. Walter owns more than 200 patented technologies in this field. Today’s full range of cutting tools and indexable cutting toolsAnchor icon are widely used in automobile, aircraft and other manufacturing industries as well as various mechanical processing industries.

Walter has brought all the latest technical achievements in the past two years, including the precision internal cooling turning toolbar, the latest fm5, RM5 guide groove inserts, the latest design of blade type thread milling cutter t2711 / t2712, etc. At the same time, it also showed the latest blade technology of Walter tiger. tec gold blade technology for customers, so that customers can get a close understanding of the charm of the golden tiger.

NO.6

Sumitomo ElectricSumitomo is one of the largest integrated tool manufacturers in Japan. More than 100 years of experience in tool manufacturing; Sumitomo provides all kinds of turning blades, milling inserts, Sumitomo turning arbors, milling arbors, Sumitomo cutting tools, Sumitomo cylindrical turning tools, Sumitomo inner hole boring tools, Sumitomo grooving tools including end face groove, outer circular groove, inner hole groove, and other grooving tools, Sumitomo solid carbide milling tools. Discarded milling cutter, cutter bar, blade, solid carbide bit, internal cooling bit, trans Soviet bit, etc.

Today’s Sumitomo products have been widely used in automobile, aerospace, shipbuilding, household appliances, and many other industries, especially its CBN and PCD tools, crankshaft milling tools, cemented carbide ZX coated drill bits and milling inserts and other products are famous in the world. In the aspect of face milling cutter, for example, the series of face milling cutter products for the plane processing of engine cylinder block and cylinder head adopts the tooltip reference type, dense tooth type, and quick-change mechanism, and can adopt high-speed feed, rough and finish machining, with rich classification and strong pertinence.

Sumitomo Electric new products include the new materials of stainless steel and steel parts turning, Sumitomo Electric’s superior products CBN series, slotting turning tool, expanding chip breaking groove, countersink drilling bit, m-grade blade, negative chip breaking groove, small diameter cutter head, high-efficiency milling cutter head, adhesive-free polycrystalline diamond, etc. For stainless steel turning, precision machining of small parts and other new products are launched.

NO.7

Dijet Industry Co., Ltd.Since its establishment in 1938, Dijet Industry Co., Ltd., as a professional cemented carbide manufacturer from raw powder to finished product, has been among the best in sales and popularity in Japan.

Dijet industrial products include all kinds of cemented carbide, ceramics, cermet, cubic boron nitride (CBN), polycrystalline diamond (PCD) and other materials, as well as all kinds of cutting tools, cemented carbide molds, special wear-resistant products, etc. Users throughout the automobile, motorcycle, machine tools, machinery manufacturing, mining, civil engineering, smelting, rolling, electronic and electrical industries, as well as other small and medium-sized tool manufacturing companies.

At present, there are 200 sets of high-precision CNC grinding equipment, more than 100 sets of CNC machining center, sintering furnace, molding machine and electric machining equipment, each with more than 50 sets. Six coating furnaces and three hip systems, etc.

NO.8

Mitsubishi materialsMITSUBISHI comprehensive materials, as a comprehensive material manufacturer, takes cement, aluminum, copper and processing industries as the pillars to provide advanced products, energy, high-performance materials and precious metals to the industrial society. Silicon products and other basic materials.

Mitsubishi integrated materials began to manufacture superhard tools under the name of “tridia” in 1931. The superhard products division produces cutting tools, wear-resistant tools and construction tools for turning, milling and drilling in Japan, and sells them to the global market, occupying the highest market share in China.

Mitsubishi integrated materials provide customers in the automotive and aircraft industries with indispensable parts processing superhard products and sintered parts as the core parts of engines, transmissions, etc.

NO.9

KennametalKENNAMETAL was founded in 1938. At that time, Philip M. McKenna, an American metallurgist, invented a new tool material of tungsten titanium alloy after years of painstaking research, which could improve the machining efficiency of cutting steel. Based on this invention, Philip founded McKenna metals in Latrobe, Pennsylvania.

Kennametal’s cutting tool products were widely used in the wartime economy. After World War II, Kennametal began to research and develop cemented carbide materials with better toughness and wear resistance. In the mid-1940s, Kenner took the lead in developing cemented carbide tools for the mining industry, which promoted the development of continuous mining machinery.

NO.10

Zhuzhou Diamond Cutting Tools Co., Ltd.Zhuzhou Diamond Cutting Tools Co., Ltd., established in June 2002, is located in the national high tech Industrial Development Zone of Zhuzhou City, Hunan Province, with wholly-owned sales subsidiaries in the United States and Germany. It is a leading integrated supplier of cemented carbide cutting tools in China, integrating production, research and marketing.

Zhuzhou Diamond provides users with indexable numerical control blades and supporting high-precision tools for high-precision turning, milling, boring and milling, drilling pin, cutting, grooving and thread processing, as well as various high-quality welding blades, clamping blades, carbide hole processing tools and tool systems. Different needs to map and sample production of all kinds of cutting tools, to provide a complete set of mechanical manufacturing solutions.

How to sharpen carbide lathe tools?2021-07-06T08:09:04+00:00

The grinding tool is a work that needs patience, time, skill and even talent. Even if the fixed angle grinder is used, it can only solve the problem of fixed angle (the most difficult technology in the grinding tool technique). However, all other requirements can not be less, and patience, time and correct operation method are still needed to grind out sharp and durable tools.

Types of turning toolsWhether it meets the technical needs of sharpening is the best standard to test the quality of the sharpener, not in terms of simplicity or complexity. The fast sharpener is the simplest, but its essence is scraping rather than grinding. The effect is very poor, the sharpness is close to rough grinding, and the retention is even worse.

Because of the consideration of efficiency and workers’ technical problems, large factories changed their cutting tools to machine clamping tools long ago, so it is difficult to see lathe workers sharpening tools. Some lathe workers even think that sharpening is very dirty and hard, and secretly change the cutting tools to machine clamping tools. I don’t know that this kind of replacement makes them lose the opportunity to practice their skills and deeply understand the cutting tools. If you don’t have the basic knowledge of tool understanding, then you can’t choose the right clamping tool and blade.

Turning tool grinding is a basic operation with high technical content in cutting. The operator needs to be familiar with the relevant theoretical knowledge and grinding principle, and master the grinding method and operation skills.

The posture and method of sharpening turning tool are as follows:

Posture and method of turning tool sharpening

  • People stand on the side of the grinder to prevent the fragments from flying out to hurt people when the grinding wheel is broken;
  • The distance between the two hands holding the knife is released, and the two elbows are clamped at the waist to reduce the shaking when grinding the knife;
    When grinding, the turning tool should be placed in the horizontal center of the grinding wheel, and the tip of the tool should be slightly upward for about 3 °~ 8°, When the turning tool contacts the grinding wheel, it should move horizontally in the left and right directions. When the turning tool leaves the grinding wheel, it should be lifted up to prevent the grinding edge from being damaged by the grinding wheel;
  • When grinding the flank, the end of the cutter bar is deflected to the left by an angle of main deflection angle; When grinding the flank of a pair, the end of the cutter bar is deflected to the right by an angle of a pair deflection angle;
  • When sharpening the arc of the tooltip, the front end of the tool is usually held by the left hand as the fulcrum, and the rear end of the tool is rotated by the right hand.

How to select the grinding wheel according to the material of the corresponding tool?

Name Tool material Advantage
White corundum grinding wheel It is suitable for common grinding of high-speed steel toolsanchor icon, cemented carbide toolsanchor icon, quenched steel tools, etc. It is suitable for high hardness and dry grinding of high-speed steel, stainless steel and other workpieces which are easy to deform and burn.
Chrome corundum grinding wheel Suitable for steel, alloy steel, quenched steel internal grinding and forming grinding, tool grinding, profiling grinding, instrument parts precision grinding, high finish. White corundum-derived varieties, rose red, toughness, good grinding finish, good angle retention.
Single crystal corundum wheel It is suitable for high hardness and dry grinding of high-speed steel, stainless steel and other workpieces which are easy to deform and burn. It is of spherical multi-angular structure, yellow and white, with high hardness and toughness. Strong cutting force.
Posture and method of turning tool sharpening

Sharpening safety knowledge

  • Before sharpening the tool, first, check whether the grinding wheel has cracks and whether the grinding wheel shaft nut is tightened, and use it after the trial run, so as to prevent the grinding wheel from breaking or flying out to hurt people.
  • The tool should not be sharpened too hard, otherwise, the hand will slip and touch the grinding wheel surface, resulting in industrial accidents.
  • Wear protective glasses when sharpening to avoid grit and iron filings flying into the eyes.
  • Do not stand in the direction of rotation of the grinding wheel when grinding, in case of accidents.
  • When grinding the small cutter head, the small cutter head must be installed on the cutter bar.
  • The clearance between the grinding wheel bracket and the grinding wheel shall not be greater than 3 mm. If it is too large, it shall be adjusted properly.
What is tungsten carbide?2021-05-21T03:03:43+00:00

Tungsten carbideis a compound composed of tungsten and carbon, the molecular formula is Wc, and the molecular weight is 195.85, tungsten carbide is a black hexagonal crystal, with metal gloss, hardness is similar to diamond, for electricity, and hot conductors. Tungsten carbide is insoluble in water, hydrochloric acid, and sulfuric acid, soluble in mixed acids of nitric acid-hydrofluoric acid. Pure tungsten carbide is fragile, if a small amount of titanium, cobalt is incorporated, it can reduce brittleness.

Tungsten carbide used as steel cutting tools often add titanium carbide, tantalum carbide, or mixtures thereof to improve explosion resistance. The chemical properties of tungsten carbide are stable. Tungsten carbide powder is applied to cemented carbide production materials.

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Name Chemical formula Molecular weight CAS number EINECS number Melting point MDL number
Tungsten Carbide WC 195.85 12070-12-1 235-123-0 2870℃ MFCD00011464
Boiling point Water solubility Density Appearance Security description Resistivity
6000℃ no 15.63g/cm³ Black hexagonal crystal with metallic luster S22,S24/25 19.2×10-6Ω·cm
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Content

  1. Brief history
  2. Physical and chemical properties
    ▪ Physical properties
    ▪ Chemical properties
  3. Production method
  4. Application field
  5. Precautions
  6. Storage and transportation
  7. Safety information
    ▪ Safe terminology
    ▪ Risk terminology
  8. Calculate chemical data

Brief history

Since 1893, German scientists have removed tungsten carbide by using tridete and carbon to heat to high temperatures and attempt to use their high melting point, high hardness and other characteristics to substitute a diamond material. . However, industrial applications have been unable to obtain industrial applications due to the criticism of tungsten carbide, easy to crack and toughness.

In the 1920s, German scientist Karl Schroter found that pure tungsten carbide can not be adapted to the fierce stress changes formed during the draw, only the low melting point metal is added to the WC to make the blank without reducing the hardness. Has a certain toughness. Schroter first proposed a method of powder metallurgy in 1923, to mix tungsten carbide and a small amount of ferrous metal (iron, nickel, cobalt), then press molding and sintering over hydrogen at a temperature above 1300 ° C, Sintering. Patent.

Physical and chemical properties

Physical nature

Microhardness Elastic Modulus Compressive strength Thermal expansion coefficient
17 300 MPa 710GPa 56MP 6.9×10-6/K

Crystallize the black hexagonal crystal system. Soluble in alfluenzaic acid and hydrofluoric acid mixed with hydrofluoric acid, insoluble in cold water. [1]

Gray with metal glossy powder. It belongs to the hexafang crystal system. Very hard, the elasticity is also large (72700kg / mm2).
Tungsten carbide powder particle size:

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Chemical nature

The air is activated and oxidized, and the antioxidant capacity is weak.
Strong acid resistance.
Chemical Reaction: W + C = WC Note: Reaction at 1150°C.
It is less than 400°C without chlorine; at room temperature to be fiercely reacted with fluorine; oxidized into tungsten oxide when heated in air.

Tungsten carbide molecular formula

Production method

The metal tungsten and carbon are raw materials, and the average particle diameter of 3 to 5 μm is dry mixed with a carbon black ball mill, after sufficiently mixing, press molding and placed in graphite disc, then in graphite resistance furnace Or heating from 1400 to 1700℃ in the induction electric furnace, preferably 1550 to 1650℃.

In the hydrogen stream, W₂C was initially formed and continued to react at high temperatures to generate WC. Alternatively, hexacarbonyl tungsten is first decomposed in 650 to 1000℃, and the tungsten powder is thermally decomposed in the CO atmosphere, and then the WC is obtained from the carbon monoxide at 1150℃, and the temperature is higher than the temperature. W₂C.

Tungsten carbide metallographic

Chemical reaction:

2W + C = W₂C
W + C = WC

The tungsten oxide WO₃ hydrotreated was reduced to prepare tungsten powder (average particle size 3 to 5μm). The tungsten powder is then pressing the mixture of the carbon black (mixed with a ball mill drying by a ball mill), and press molding at a pressure of around 1T / cm². The pressurized molded block is placed in a graphite disc or a crucible, and the graphite resistance furnace or the induction electric furnace is heated to 1400 to 1700℃ (preferably 1550 to 1650) with a graphite resistance furnace or induction electric furnace (pure hydrogen using a dew point of -35℃) (preferably 1550 to 1650)℃) so that the carbon is carburized to form a WC.

The reaction begins around tungsten particles because W₂C is generated in the initial stage of the reaction, since the reaction is not complete (mainly low in reaction temperature), except for unreacted W and intermediate product W₂C in addition to the WC. Therefore, it must be heated to the above high temperature. The highest temperature should be determined according to the size of the raw material tungs. If the average particle size is between 150μm, the reaction is carried out at a high temperature of 1550 to 1650℃.

Chemical reaction:

WO₃ + 3H₂ → W + 3H₂O
2WO₃ + 3C → 2W + 3CO₂
2W + C = W₂C
W + C = WC

The carbon tungsten carbide WC particle size is used according to the hard alloy of different purposes, using different particle size tungsten carbide; hard alloy cutter, such as cutting machine blade V-CUT knives, finishing alloy adopts superfine Dine particle tungsten carbide; coarse processing alloy adopts medium-granulated tungsten carbide; alloys in gravity cutting and heavy cutting of coarse particles do raw materials; mine tool rock hardness high impact load is large with crude particulate tungsten carbide; rock impact small impact load Small, using medium particulate tungsten carbide to do raw material wear parts; the Lord.

Tungsten carbide theory contains 6.128% (50% atom), and free carbonization (Wc + C) occurs in tungsten carbon tungsten carbon, and free carbon is sintered when carbonized carbon content is greater than the theoretical amount of carbon. The tungsten grain grew up, causing the hard alloy crystal grains uneven; tungsten carbonized carbon high (≥6.07%) free carbon (≤0.05%), the total carbon is determined in the production process and scope of use of cemented carbide.

Under normal circumstances, paraffin process vacuum sintered tungsten carbon tungsten carbon mainly decided that the compound oxygen content in the sintered front block contains a part of oxygen to increase by 0.75 parts of carbon, Tc total carbon = 6.13% + oxygen content% × 0.75 (assuming sinter In the furnace, the neutral atmosphere is actually the carbonized carbon tungsten carbon tungsten carbon tungsten carbon tungsten carbon carbon carbon carbon carbon atmosphere is less than the calculated value). China’s total carbon content is generally divided into three paraffinic process vacuum sintered with tungsten carbon tungsten carbon, about 6.18±0.03% (free carbon will increase) paraffin process hydrogen sintering tungsten carbonate total carbon content is 6.13 ± 0.03 % Rubber process hydrogen sintering Tungsten carbide total carbon = 5.90±0.03% The above process sometimes cross-proceeds, thus determining total carbon carbon tungsten carbon according to specific situations.

Different use ranges, different cobalt content, total carbon of WC used in different grain size alloys can do some small adjustments. Low cobalt alloy can be used for tungsten carbide of total carbon, and high cobalt alloy can be used for tungsten carbide with low carbon. In summary, the specific use requirements of the carbide use different requirements for tungsten tungsten tungsten particles.

Application field

  • Used as a tungsten carbide end mill, a tungsten carbide woodworking spiral cutter head, a high-speed cutting vehicle, a kiln structural material, a jet engine component, a metal-ceramic material, a resistance heating element, and the like.
  • For use in the manufacture of a cutting tool, a wear-resistant component, copper, cobalt, and a molten crucible, a wear semiconductor film.
  • Used as ultra-hard tool materials, wear-resistant materials. It can form solid solutions with many carbides. WC-TiC-Co hard alloy tool has been widely used. It can also be used as modified additives for NBC-C and TAC-C ternary systems, which can reduce sintering temperatures, and maintain excellent performance, and can be used as aerospace materials.
  • Tungsten carbide (WC) powder is synthesized with tungsten anhydride (WO₃) and graphite at a high temperature of 1400 to 1600°C in a reduced atmosphere. The dense ceramic article can be obtained by thermostat sintering or thermostatic sintering.
UKO's CNC Coated End Mill

Precautions

Health hazard: tungsten dust can cause bronchial periharmonitis, fine branch tracheitis, latching fine bronchitis and atrophic emblem. Tungsten carbide can cause hyperplasia reactions in lung lymphoid cells and gradually crash. The vessel wall thickened and uniform. In the work, the person who contacted tungsten carbide dust, the gastrointestinal dysfunction, the kidney was stimulated, and the upper respiratory tract appeared. The highest allowance concentration of tungsten carbide is 6mg/m³. The highest allowable concentration of 1mg/m³ in the US soluble tungsten compound (according to the tungsten meter), an insoluble tungsten compound (according to the tungsten meter) is 5mg /m³.

UKO's Coated Indexable Inserts

Safety: Use a gas mask, dust uniform, gloves, glasses that meet the requirements. Dust leakage should be prevented at all stages of production. Workers must do physical examination before employment, check once a year. When there is obvious symptom of the upper respiratory tract, it is temporarily mobilized, detached from tungsten contact. When the pulmonary hardening or external respiratory is disordered, it should be lowered.

Storage and transportation

Storage: Storage in a cool, dry warehouse, pay attention to the packaging container in the transportation, rain and anti-Japanese light exposure.

Packaging Storage and Transportation: The product uses a iron barrel (plastic bucket), the lined polyethylene plastic bag sealing package, the net weight of each bag must not exceed 50kg. There should be “moisture-proof” and “up” and other words on the outer packaging bucket. The product should be stored in a cool, dry warehouse, pay attention to the packaging container in the transportation, rain and anti-Japanese light exposure.

Safety information

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Security terminology

S22 Do not inhale dust.
S24 / 25 AVOID Contact with Skin and Eyes.

Risk terminology

R23 is inhaled toxic.

  • Calculation reference value (XLOGP): NO
  • Hydrogen bond donor quantity: 0
  • The number of hydrogen bond receptors: 1
  • Can rotate chemical bonds: 0
  • The number of tautomers: no
  • Topological molecular polar surface area: 0
  • Heavy momentum quantum: 2
  • Surface charge: 0
  • Complexity: 10
  • Isotope atom: 0
  • Determine the number of atomic integers: 0
  • Uncertain Atomic Center Number: 0
  • Determine the number of chemical key structure: 0
  • Uncertain chemical key structure center quantity: 0
  • Number of covalent keys: 1