Study On The Uniformity Of Hot Deformation Microstructure Of 430 Ferritic Stainless Steel

Ferritic stainless steel has the characteristics of high thermal conductivity,small expansion coefficient,good oxidation resistance and excellent stress corrosion resistance.However,surface wrinkles occur during stretching and deep drawing.Present research results show that the coarse grain band is easy to appear in the center area of the thickness direction of the rolled ferritic stainless steel cold rolled plate.Therefore,in this paper,430 ferritic stainless steel is taken as the research object,in order to obtain uniform hot deformation structure,thermal simulation experiments and hot rolling experiments are carried out respectively,and effects of hot deformation process parameters such as reduction,deformation pass,deformation temperature and deformation rate on the microstructure uniformity of 430 ferritic stainless steel are mainly studied.The microstructure,EDX spectrum and texture of the samples were observed by metallographic microscope,scanning electron microscopy(SEM)and X-ray diffraction.The experimental results show that the microstructure of 430 stainless steel becomes more and more uniform and fine,and transforms from deformed structure into recrystallized structure with the increase of deformation during hot deformation.Increasing the amount of hot compression deformation and the amount of hot rolling reduction is beneficial to obtain uniform deformation structure in the thickness direction of the strip.With a lower reduction rate,the uniformity in the thickness of the 430 stainless steel sample obtained after hot deformation is higher.When the hot compression deformation temperature is low,the uniformity in the thickness direction of the 430 stainless steel sample deteriorates.After the 430 stainless steel is hot rolled with large reduction,the microstructures in thickness direction are uniform,no coarse crystal band appears in the microstructure of cold-rolled plates,and there is no wrinkle defect appears in the tensile sample.Therefore,the surface wrinkle defects in 430 stainless steel can be effectively alleviated or even eliminated by using large reduction during hot rolling process.