Since using cold-rolled ribbed steel bars has obvious technical and economic benefits, its demand in the construction market is also increasing rapidly, driving the development of domestic cold-rolled ribbed wire bar production. Then the quality of ribbed wire bars produced by some enterprises can not meet the requirements of the national standard GB13788-92. There are two main reasons:
- The process does not meet the criteria.
- The quality control means are not perfect.
The production mode of cold-rolled ribbed wire is divided into active and driven processes according to the transmission mode of the rolling mill. The whole production line consists of the following procedures: pay-off machine, descaling machine, wire drawing machine, cold rolling machine, stress relief device, take-up machine, butt welding machine, etc. To ensure product quality, the production line must meet the requirements of the following process flow.
Uncoiling → descaling → lubrication → drawing, rolling, and reducing → rib cutting and rolling → stress relief → winding up → inspection one by one → listing and stacking.
Uncoiling is also called paying off. According to different requirements, overhead paying-off or horizontal paying-off can be used if the coil weight of the wire rod is small (like a double wire rod), the welding machine should also be paired after uncoiling.
For descaling, the repeated bending method is adopted. The descaling machine comprises 4-6 rollers with a diameter of 100-150MM. The rolling groove is welded with a layer of hardened protective layer. The roll wheel is adjusted to the proper position when the device is started. When the steel bar passes through the roll wheel, it will bend to remove the oxides and pollutants on the steel bar surface.
Lubrication: the screw feeder continuously presses the lubricant to the wire rod and enters the drawing and rolling process. The lubricant can be talc powder, molybdenum disulfide, or soap.
REDUCING AND RIB-CUTTING ROLLING
Reducing and rib cutting rolling. This is the main part and one of the key processes for producing cold-rolled ribbed wire. Y-type three rolls are arranged 120 degrees from each other.
- The active production line consists of four collective drive Y-type tandem cold rolling mills, with four groups of Y-type rolls, the first three groups for reducing the diameter and the fourth group for rib cutting. Each rolling mill can be interchanged after changing the hole shape.
- The driven production line is composed of two rolling mills and four groups of rolls, the first three groups are used for reducing diameter, and the fourth group is used for rib cutting.
- The roll is installed on the bearing and can be adjusted individually or in groups of three. The adjustment of rolls plays a very important role in the quality of finished products.
MECHANICAL STRESS RELIEF
Mechanical stress relief is one of the indispensable processes in the production of cold-rolled ribbed steel bars.
Winding up: It is mainly composed of an alkali speed drive, braking device, smooth rod wire arrangement device, I-shaped wheel head locking device, wire reel loosening device, electrical control system, and automatic take-up counting device.
The production inspection of cold-rolled ribbed steel bars shall include three aspects. Surface inspection, base metal inspection, random inspection, and finished product inspection one by one Check. The inspector shall make original records of the inspection results for future reference.