The support roller material is used more is 9CR2Mo, carbon content of about 0.9%, Cr content of 2%, and a small amount of Mo, the material is a typical cold-rolled work roll material, after heating and severe cooling can obtain high surface hardness and certain wear resistance. Detect whether there are cracks, inclusions and other defects inside, as well as the depth of cracks and inclusions.

Vending machine accessories determine whether the amount of hardfacing repair and roll turning processing can be performed. Roll turning processing according to the process requirements unilateral cutting is not small, in 50mm hardened layer, processed into welding groove, and ensure the design thickness of the overlay layer. The processed roll surface and welded groove are fully tested to confirm that the roller does not have any defects.

Composite high chromium cast iron rolls are also successfully used in tropical rolling mills. During the same period, forged white iron and semi-steel rolls were applied in Japan. In the 80s, Europe introduced high-chromium steel rolls and cold rolls with ultra-deep hardened layers, as well as special alloy cast iron rolls for small section steel and wire rod finishing. Powder tungsten carbide roll ring, high chromium cast iron roll and other new varieties. By the 90s, China's roll production had basically met domestic needs and was partially exported, but the variety needed to be increased and the quality needed to be improved.