define

Cold rolling: hot rolled steel coil is used as raw material, the oxide skin is removed by pickling, and the finished product is rolled hard coil. Due to the cold work hardening caused by continuous cold deformation, the strength and hardness of rolled hard coil increase, and the toughness and plastic index decrease, so the stamping performance will deteriorate, and it can only be used for simple deformed parts. Hard rolling coil can be used as raw material for hot dip galvanizing plant because hot dip galvanizing units are equipped with annealing line. The rolling hard coil weight is generally 6~13.5 tons. The hot rolling pickling coil is rolled continuously at room temperature. The inner diameter is 610mm.