The hot rolled steel coil is used as the raw material, and the oxide scale is removed by pickling, and then the cold rolling is performed. The finished product is rolled hard roll, and the cold work hardening caused by the continuous cold deformation causes the strength and hardness of the rolled hard roll to rise, and the toughness index decreases. Therefore, the punching performance will deteriorate and can only be used for parts that are simply deformed. Rolled hard rolls can be used as raw materials for hot-dip galvanizing plants because the hot-dip galvanizing units are equipped with an annealing line. The hard roll weight is generally 6~13.5 tons, and the inner diameter of the coil is 610mm.
Generally, cold-rolled rolled sheets and coils should be subjected to continuous annealing (CAPL unit) or hood furnace annealing to eliminate cold work hardening and rolling stress, and achieve the mechanical properties specified in the corresponding standards.
The surface quality, appearance and dimensional accuracy of the high quality cold rolled steel coil china are better than that of the hot rolled coil, and the thickness of the product is thinly rolled to about 0.18mm, which is favored by the majority of users. Deep processing of products with cold-rolled steel coils as a substrate has become a high value-added product. Such as electro-galvanizing, hot-dip galvanizing, fingerprint-resistant electroplating zinc, high quality PPGI prepainted galvanized steel coil and vibration-reducing composite steel plate, PVC laminated steel plate, etc., so that these products have good quality, high corrosion resistance and other excellent quality, has been widely used. Cold rolled steel coils must be finished after annealing, including cutting, tailing, trimming, leveling, leveling, rewinding, or longitudinal shearing. Cold-rolled sheet punching nets are widely used in automobile manufacturing, home appliances, instrument switches, construction, office furniture and other industries.
