Effect Of Cold Rolling Technology On Structure And Properties Of 301L Stainless Steel

In recent years,the research on the body of rail vehicles become the focus because of the rapid development of rail transit.301 L stainless steel which has higher strength and good corrosion resistance can be selected as railcar body material.It is possible to achieve lightweight and energy-saving emission while ensuring the strength by deformation strengthening.Parameters of 301 L stainless steel sheet in the cold rolling process is not easy to control,therefore,in this paper,the microstructure and properties of 301 L stainless steel sheet by cold rolling with different thickness reduction ratio is studied and some study technical parameters are provided for actual production.Standard components of 301 L stainless steel are smelted in this experiment,they were forged,hot rolled and cold rolled.The microstructure and properties of 301 L stainless steel sheets by cold rolling with different thickness reduction are studied.The research shows that,in the cold rolling process,as the deformation increases,dislocation multiplication cause grain deformation by stopping the dislocations near grain boundary.The cross-slip zone appears in the grain,providing a place for martensite nucleation.At large deformation,the phenomenon of grain nanocrystallization occurs and the diffraction spots of the material are in a ring shape.Grains rotate while cold rolling,γ(220)is gradually parallel to the rolling direction.Because of work-hardening,grain refinement and martensitic nucleation,strength and hardness of the sample increase,plasticity and toughness of it decrease eventually.At 15% reduction ratio,the tensile strength,yield strength and hardness of 301 L stainless steel reaches 965 MPa,677MPa,335 HV,respectively,and the elongation rate of it is 49%.At 40% reduction ratio,the tensile strength,yield strength and hardness of it are 1317 MPa,1274MPa and 469 HV,respectively,the elongation rate of it decrease obviously.With the increase of cold rolling deformation,the uniform deformation ability of the material decreases in the subsequent tensile test,the n value of the sample decrease from 0.357% down to 0.030%.