Galvanizing line production process is: cold hard coil → degreasing → continuous annealing → galvanizing → smoothing → drawing straightening → roller coating → induction heating → air cooling → quality inspection → oil weighing and packaging. In its production, stamping cracking defects are easy to occur, which affects the production of users. Analysis of its causes are:
1. Annealing temperature
Annealing temperature is an important process parameter in the galvanizing process. Annealing temperature has a greater impact on the yield strength of the product. When the annealing temperature is low, the annealing is inadequate, the grains are fine, the strength is high, and the elongation is low; if the annealing temperature is too high, it is easy to cause the grains to be abnormally large, and the yield strength decreases while the tensile strength decreases even more. It is easy to break directly during the stamping and stretching process.
2. Processing lubrication
The surface roughness of the material will affect the oil storage capacity of the surface. The appropriate surface roughness of the steel coil is also very important for the stamping performance of the material. At the same time, the selection of the amount of oil is very important. If the amount of oil is too small, the material will not be sufficiently lubricated during the stamping process, which will cause the material to crack during stamping; if the amount of oil is too large, it will be easy to slip during the slitting and forming process. Production rhythm.
3. Material thickness and mold clearance fit
Materials in the stamping process, the gap between the mold and the thickness of the material is also an important factor leading to material cracking.
4. Defect control such as inclusions
Defects such as inclusions and intrusion of foreign objects are very unfavorable for the stamping of stamped products. Due to the insufficient local elongation of the inclusions, stamping and tensile cracking are easy to occur.
