The influence of cold rolling deformation on tensile properties and microstructures of Mn18Cr18 N austenitic stainless steel

Abstract

The tensile tests of Mn18Cr18 N austenitic stainless steel plates with rolled reductions of 10%–40% were investigated, in which the tensile loading direction is perpendicular to the direction of rolled loading. The variation of tensile properties and microstructures of rolled Mn18Cr18 N plates with different reductions were analyzed. The results show that the tensile stresses increased with increasing of rolled reductions. And the plasticity indices decreased with the increasing of rolled reductions. The maximum tensile stress value of 1394 MPa before necking was obtained at the 30% rolled reduction, the corresponding yield stress is 1092.0 MPa, and the corresponding elongation is 37.9%. The tensile microstructures observed by OM and TEM indicated that grain refinement and grain orientation occurred. Deformation microstructures characterized by planar slips, twin-like bands and twins with increasing of rolled reductions, which resulted in the increasing of tensile stresses and the decreasing of plasticity indices of the rolled plates with increasing of rolled reduction. It also caused the tensile fracture morphologies from ductile fracture with dimples to brittle fracture with cleavage steps with increasing of rolled reductions. The transition rolled reduction from ductile fracture to brittle fracture is 30%, which is independent on loading path.