Study On Texture Evolution And Grain Boundary Distribution Of 301L Stainless Steel Under Different Cold Rolling Reduction Ratios

301L stainless steel is a metastable austenitic stainless steel.Because of its high hardness,easy cold working forming and good corrosion resistance,it can also meet the requirements of car body structure forming and light weighting.This has become the first choice of stainless steel for rail vehicles.At present,scholars have carried out a lot of research work on the structural properties and production technology of 301 L stainless steel,but due to the special structure transformation of metastable austenitic stainless steel sheet during deformation,it is necessary to carry out related research on the texture evolution and grain boundary feature distribution during the cold rolling of 301 L stainless steel.This article first develops the cold rolling process of301 L stainless steel and prepares cold rolled test plates.Second,it compares and analyzes the micro structure of 301 L stainless steel in the solid solution state and different cold rolling reduction rates(3%,5%,9%,24%)hardness,tensile fracture morphology,mechanics and corrosion resistance,EBSD technology was used to study the texture evolution and grain boundary distribution of 301 L stainless steel at different cold rolling reduction rates.It was found that different cold rolling reduction rates for 301 L stainless steel the influence of microstructure properties,texture evolution,and grain boundary feature distribution.Finally,the influence of the grain boundary feature distribution on the mechanical and corrosion resistance of 301 L stainless steel is analyzed.The study draws the following conclusions:From the analysis of the microstructure and properties of 301 L stainless steel in the solid solution state and different cold rolling reduction ratios,it can be seen that with the cold rolling reduction ratio,the microstructure of 301 L stainless steel gradually changes from austenite to martensite.In the solid solution state and small cold rolling reduction ratio,the average grain size is about 20 ?m.When the cold rolling reduction ratio is 24%,the grains are significantly refined,and the average grain size is reduced to 5.25 ?m,The grains are distributed fibrous along the rolling direction.The tensile strength,yield strength and hardness of 301 L stainless steel gradually increase with the increase of cold rolling reduction,and the elongation gradually decreases.Scanning and analyzing the fractured 301 L stainless steel by SEM revealed that there were a large number of dimples at the fractures,which had the characteristics of ductile fracture.The dimples gradually became smaller and shallower with the increase of the cold rolling reduction rate.The corrosion resistance of 301 L stainless steel gradually weakened with the increase of cold rolling reduction.The EBSD was used to study the orientation distribution of IPF-Y and IPF-Z forall phases of 301 L stainless steel at different cold rolling reduction rates.Analysis showed that as the amount of cold deformation increases,the grains are elongated and flat,and the grains are inside.When the color gradation area appears,the orientation within the grains changes.With the increase of the cold rolling reduction ratio,<111>in IPF-Y and IPF-Z gradually decreased,the change in <101> in IPF-Y was not obvious,and the <101> in IPF-Z gradually increased.At a cold rolling reduction rate of 3%,the <112> content is not much.When the cold rolling reduction rate increases to 5%,<111> of IPF-Z gradually turns to <112> and <001>,which deforms with cold The increase of the amount <112> increased significantly.The cold rolling texture analysis of 301 L stainless steel at different cold rolling reduction ratios shows that 301 L stainless steel has strong ? texture({111}//ND)after cold rolling at different rolling reduction ratios.With the increase of the cold rolling reduction ratio,the {110}<112> orientation density of the austenite phase increases,the texture characteristics of brass become more obvious,and the {111}<211>orientation strength decreases.With the increase of the cold rolling reduction,the{111}<110> orientation density of the martensite phase gradually decreases,and the{111}<112> increases;the cubic rotation texture {001}<110> varies with the cold rolling reduction.Increasing the orientation density is low and the strength is relatively stable;in the ? orientation line,the {111}<112>~{332}<112> region texture strength gradually increases with the increase of the cold rolling reduction rate.The grain boundary characteristic distribution of 301 L stainless steel was studied under different cold rolling reduction ratios.The results show that as the cold rolling reduction ratio increases,the small-angle grain boundaries increase of 301 L stainless steel,and the CSL strong grain boundaries of ??29 and large-angles grain boundaries proportion decreased.Because the elongation of the material is related to the poor grain boundary orientation and special grain boundary distribution,and under a certain cold rolling reduction ratio,more small-angle grain boundaries and fewer large-angle grain boundaries can hinder crack propagation and material fracture.As the cold rolling reduction increases,the elongation of 301 L stainless steel decreases and the plastic toughness decreases.The ?3 grain boundary gradually decreases with the increase of the cold rolling reduction rate.When the cold rolling reduction rate increases from 9% to 24%,the reduction of the ?3 grain boundary content is smaller.