Pulsed current-assisted twelve-roll precision rolling deformation of SUS304 ultra-thin strips with exceptional mechanical properties

Innovative pulsed current-assisted multi-pass rolling tests were conducted on a twelve-roll mill during the rolling deformation processing of SUS304 ultra-thin strips. The results show that in the first rolling pass, the rolling reduction rate of a conventionally rolled sample (at room temperature) is 33.8%, which can be increased to 41.5% by pulsed current-assisted rolling, enabling the formation of an ultra-thin strip with a size of 67.3 μm in only one rolling pass. After three passes of pulsed current-assisted rolling, the thickness of the ultra-thin strip can be further reduced to 51.7 μm. To clearly compare the effects of a pulsed current on the microstructure and mechanical response of the ultra-thin strip, ultra-thin strips with nearly the same thickness reduction were analyzed. It was found that pulsed current can reduce the degree of work-hardening of the rolled samples by promoting dislocation detachment, reducing the density of stacking faults, inhibiting martensitic phase transformation, and shortening the total length of grain boundaries. As a result, the ductility of ultra-thin strips can be effectively restored to approximately 16.3% while maintaining a high tensile strength of 1118 MPa. Therefore, pulsed current-assisted rolling deformation shows great potential for the formation of ultra-thin strips with a combination of high strength and ductility.