Microstructure and mechanical properties of SUS304 ultra-thin strip rolled with electric pulse assistance
SUS304 stainless steel ultra-thin strip is an important raw material for many high-precision fields,and its large deformation resistance leads to complex rolling production processes for ultra-thin strips.Pulse current was loaded into the rolling deformation of SUS304 ultra-thin strip to study the effect of pulse current assistance on the rolling deformation of ultra-thin strip.Through room temperature rolling and electric assisted rolling experiments at different pulse frequencies,EBSD and XRD were used to characterize the microstructure of the rolled samples,and the effects of electric pulse assisted rolling on the microstructure morphology,grain orientation,and phase evolution of ultra-thin strips were studied.Combined with mechanical property tests,the effect of pulse current on the mechani-cal properties of rolled specimens was analyzed.The results indicate that electric pulse assisted rolling promotes dynamic recovery of the sample,and increasing the frequency of the electric pulse can accelerate its dynamic process,with sub-structural grains predominating in the 600 Hz energized rolled samples(98.3%).Loading pulse current can change the rolling deformation mechanism of ultra-thin strip from phase transformation martensite to deformation-induced twinning.The thermal and non-thermal effects generated by pulse current can promote disloca-tion detachment,resulting in a significantly lower dislocation density in electrically rolled samples under the same deformation compared to the room temperature rolled sample,weakened work hardening,and improved mechanical properties.At the same time,electric pulse assisted rolling helps to weaken the rolling deformation texture and increase the type of texture,which can improve the anisotropy of the deformed sample,and is conducive to improving the plastic deformation ability of the sample.Compared with the room temperature rolling sample,the microhardness of the 600 Hz electrified rolling sample decreased by 33.4%,the yield strength decreased by 15.2%,the fracture elongation increased by 249.6%,and the plastic deformation ability restored to 30%of the raw material.It can be seen that pulse current assisted SUS304 ultra-thin strip rolling deformation can reduce work hardening,reduce defor-mation resistance,and improve plastic deformation ability.It is expected to break through the minimum rollable thickness and expand its application fields.
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