How is the strip structure of the packaging steel strip produced? How to eliminate?

How is the strip structure of the packaging steel strip produced? How to eliminate?
The band structure of 　　 steel refers to that after the structural steel is hot processed, ferrite and pearlite form a layered parallel alternating band structure along the direction of deformation. Caused by improper processing.
　　Dendrite segregation during the casting process will enrich the internal impurities and alloying elements between the branches, so the phase transition point in this region is higher. In the process of hot working, the enriched area of u200bu200bimpurities and alloying elements will be distributed along the deformation direction of the processing. The cooling rate is slow after processing, and the eutectoid ferrite will be preferentially folded out, and the carbon will be squeezed out to the nearby austenite. In the tensite, the carbon content there is increased and then transformed into pearlite. Pre-eutectoid ferrite precipitates in strips along the fiber direction of the impurities into alloying elements, while pearlite is formed between the flake ferrites. The band-like structure formed in the steel will cause the reduction of the transverse plasticity and toughness of the steel, the deterioration of the cutting performance of the steel, and the increase of the heat treatment deformation and the unevenness of the hardness of the steel, so it should be eliminated.
　　 Two normalizing treatments should be used for the banded structure that appears, the first high temperature normalizing (900℃*2.5h, air cooling), the purpose is to eliminate the banded structure, the second normalizing (860℃*2h) , Air cooling), can refine the grain, reduce the hardness, improve the machinability, suitable for 40Cr, 40MnVB, 45MnB steel forging stock. In addition, the cooling rate after hot working is increased, and the band structure is reduced and eliminated by repeated forging.