Research On Tandem Cold Rolling Process Of SUS304Stainless Steel

SUS304stainless steel has a high work-hardening rate and large deformation resistance in cold rolling process, so generally in actual production multi-pass cold rolling (20-roll Sendzimir mill) is applied. But there are some problems such as low production efficiencies and high cost in multi-pass rolling process. With Baosteel Stainless Steel Co., Ltd.’s research project of300series stainless steel tandem cold rolling process as background, This article carried out research work of work hardening and tandem cold rolling process of SUS304stainless steel, and the following research results were obtained:With the degree of cold rolling deformation increasing, yield and tensile strength of SUS304stainless steel increased sharply, and elongation decreased. With the deformation temperature (deformation zone strip temperature:room temperature～200℃) elevating, yield strength decreased slightly, and the tensile strength and elongation decreased in a small amount of deformation, however, the tensile strength and elongation did not change significantly in the large deformation. Resistance model of SUS304stainless steel cold rolling was built with consideration of temperature affect.In cold rolling process, with the amount of deformation increasing, the grain deformation degree increased, a large number of defects such as twins, lath martensite and dislocation pileup appeared in the microstructure.After solution treatment, there were massive annealing twins in the microstructure, with the increasing of pre-deformation degrees, annealing microstructure changes from status of not full recrystallization gradually to full recrystallization and then to microstructure grain growth, and with the increasing of deformation average grain size decreases firstly then increases. Solution annealed microstructure didn’t show specific grain-orientation, and a high proportion of coincidence site lattice appeared in the microstructure.Combined with conditions of site producting in1750unit, a lot of SUS304stainless steel cold rolling tests were conducted in laboratory, achieving calculation of strip temperature in deformation zone, calculation of deformation resistance and calculation of rolling force models in different processes. A process regulation of field trial rolling of SUS304stainless steel was made, and the regulation achieved good results.Against to problems of F1frame rolling force too high and T45undulation too large in field trial rolling, combined with calculation of the rolling force model and the rolling force FEM, and tandem cold rolling process regulations of SUS304suited for practical product on site was developed. On-site device was checked, layed the foundation for exerting device capacity to the greatest extent and realizing massive yielding.