Brief introduction to the purpose of flattening the raw material of packaging steel strip

Brief introduction to the purpose of flattening the raw material of packaging steel strip
　　The cold-rolled strip steel after recrystallization and annealing needs to be leveled to improve the performance, flatness and surface quality of the cold-rolled strip. Flattening is actually a cold rolling process with a small amount of deformation. Generally, the elongation is 0.5-3%, and in some cases, it is 5% or even 10%. The use of a larger extension control rate is mainly to improve the strength and hardness of the strip.
　　The flatness of cold rolled strip is an important quality index. Flattening can reduce or eliminate the wave shape generated during rolling, improve the flatness of the strip, and thereby improve the quality of the product. In order to improve the flatness of the strip, the roll diameter of the leveler should be selected as large as possible, which is beneficial to the improvement of the plate shape.
When 　　 is flat, according to the requirements of the product, three kinds of roll surface states: polished, polished and sandblasted can be used to obtain different strip surface roughness.
　　 Rolling surface defects, such as roll imprinting, folding, etc., can be eliminated or reduced by leveling, and leveling can increase the first-class product rate by 10-20%.
　　The thickness uniformity of the flattened steel plate has also been improved. For example, the thickness difference between the two sides and the middle of the flattened steel plate is 0.02m before flattening, and it is reduced to 0.01mm after flattening.
　　Deep-drawing steel must be flattened in order to eliminate the yielding platform and improve the deep-drawing performance.