1. Hot rolling
Continuous casting slabs or blooming slabs are used as raw materials, which are heated in a walking heating furnace. After phosphorus removal with high-pressure water, they enter the rough rolling mill. The rough rolled material is cut into the head and tail and then enters the finishing mill. Computer-controlled rolling, after final rolling, it is cooled by laminar flow and coiled by a coiler to become straight coils. The head and tail of straight hair curlers are often tongue-shaped and fish-tail-shaped, with poor thickness and width accuracy. The edges often have defects such as wavy shapes, folded edges, and tower shapes. The coil weight will be heavier, and the inner diameter of the steel coil is 760mm. After the straight coils are processed by head cutting, tail cutting, edge trimming and multi-pass straightening, leveling and other finishing lines, they are then cut into plates or re-rolled to become hot-rolled steel plates or flat hot-rolled steel coils. , slit belts and many other products.
2. Cold rolling
Cold rolling uses hot-rolled steel coils as raw materials. After pickling to remove oxide scale, cold rolling is performed. The finished product is hard-rolled coils. The cold work hardening caused by continuous cold deformation increases the strength and hardness of hard-rolled coils. As the index of toughness and plasticity increases, the stamping performance deteriorates and it can only be used for parts with simple deformation. Hard rolled coils can be used as raw materials in hot-dip galvanizing plants because hot-dip galvanizing units are equipped with annealing lines. The weight of hard-rolled coils is generally between 6 and 13.5 tons, and the inner diameter of the steel coil is 610mm. Generally, cold-rolled plates and coils should undergo continuous annealing or de-annealing in a bell furnace to eliminate cold work hardening and rolling stress, and achieve the mechanical properties specified in the standard.
