Cold rolled steel increases in hardness after a rolling process and requires softening to enable the steel strip.
The strip is to be drawn or shaped for special applications like drum making, white goods, automobile parts. The strip is cleaned in an electrolyte and alkaline bath to remove residual oil and dirt from the strip. After the cleaning process the coils are annealed in the Bell furnaces.
Annealing is a process of heating the steel coils in a controlled temperature and atmosphere zone and subsequently cooling the coils. This controlled heating and cooling reduces the hardness of the steel and makes it more ductile or malleable. After the annealing process, the strip is then skin-passed to improve the flatness of the strip with controlled elongation and rolling.
PT AM/NS uses High Convection Hydrogen (HICON) annealing to achieve better quality on the soft products. The HICON annealing process from Ebner, Austria uses inert-hydrogen atmosphere in the process chamber, which is circulated with variable speed fans to ensure uniform temperature and soaking of the coils. The resulting strip is ultra-bright with uniform mechanical properties, free of any residual carbon from the strip oil. Advanced protection systems ensure total operating safety with Hydrogen.
Skinpassing, a light cold rolling operation, is employed to improve flatness, produce the final surface finish or texture, develop mechanical properties, and/or reduce the tendency of stretcher strain or fluting during forming.
Soft products are mainly applied in the automobile industry, drum making, pipe
and tube industry, white goods appliances and furniture and involve a very stringent quality control to suit the customer's application.