Tensile deformation characteristics of Cr15Mn9Cu2Ni1N stainless steel slab at elevated temperature

For Cr15Mn9Cu2Ni1N stainless steel slab,the occurrence of strain localization during the hot deformation may cause surface defects.Small specimens were cut from the surface layer and the core of a slab,and tension tests were performed on thermal-mechanical testing machine at 950℃~1150℃.Experimental results show that,with the increase of deformation temperature the strength are decreased and percent elongation increased.Before the occurrence of necking or strain localization,specimen experienced two stages including uniform deformation and necking diffusive deformation,both of which causing deformation zone of specimen to obtain macroscopic uniform appearance.The percent elongation of hot tensile test is mainly dependent on the deformation during the stage of necking diffusion.It is understood that during stage of uniform deformation the inhibition of strain localization is mainly depended on strain hardening;during stage of necking diffusive deformation strain rate hardening played a vital role in obtaining larger macroscopic uniform deformation.With the increase of deformation temperature,particularly as temperature higher than 1100℃,strain rate hardening effect of this steel is strengthened,and the occurrence of necking is postponed,thus bigger percent elongation is obtained.