What are the factors controlling the wire drawing process?
In metal processing, using external force to let carbon steel, stainless steel, aluminum, copper and other metals forced through the drawing dies, 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 and 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.