Cold Rolled Steel

Cold Rolled Steel
Cold rolled sheet is further rolled from hot rolled steel. It is widely used in auto parts and electrical appliance manufacturer. Due to rolling without extra heating, the cold rolled steel is clean on surface, bright and high accuracy.
The thickness accuracy of cold rolled products is determined by the cold rolling process. Rolling force and strip tension are computer-controlled to minimize thickness deviations during rolling, based on measurements of the strip thickness at the entry and delivery sides of the mill.

Cleaning
Rolling oil on the cold rolled strip is burned off during annealing, which is the next process after cold rolling. Other types of rolling oil are removed by electrolytic cleaning prior to annealing. In particular, electrolytic cleaning is used with products which require a clean surface to ensure good paintability.
The formality of products is determined by annealing. Because cold rolling significantly increases material hardness, making forming difficulty, annealing is performed to improve ductility by inducing a recrystallized structure in the steel. As the annealing process, coils are piled and covered by the box and annealing process, coils are piled and covered by the box and annealled and this is called the batch annealing. The other is the continuous annealing process, in which coils are continuously treated.

Common Defects
The accumulation of large inclusions on the edges is one of the main sources of induced edge cracking. Because the thin slab adopts a funnel-type crystallizer, the flow, heat transfer unevenness and liquid level fluctuation inside the crystallizer are more complicated than the traditional slab continuous casting. Surface inclusions are formed on the surface of the slab, where larger inclusion particles are deposited on the side of the slab, resulting in the enrichment of large oxide inclusions on the side.
The primary scale that was not completely removed was pressed into the strip during the subsequent rolling process, causing strip surface defects. The reason that the secondary descaling water has not been turned on is the key to the intrusion defect of the secondary scale. The defect tracking results show that the intrusion defects of iron scale can be basically eliminated in the subsequent pickling and cold rolling process, which basically has no effect on the cold rolled sheet.