The influence of hot-rolling reductions and passes on the microstructure and mechanical properties of Mn18Cr18N ESR steel

Abstract

The single-pass hot-rolling process with height reductions of 15 %, 30 %, 40 % and 50 %, and the three-pass and the five-pass hot-rolling processes with 60 % total reduction, were carried out for Mn18Cr18N ESR steel slabs. The influence of the hot-rolling reductions and passes on the microstructure and mechanical properties of the rolled samples was investigated. For the single-pass rolled process, the volume fraction of the refined dynamically recrystallized grains increased with the increasing of the reduction, both the tensile strength and elongation also increased with the increasing of the reduction, and the fracture morphology transformed to ductile at higher reductions. For the three-pass and the five-pass rolling processes, strain-hardening structures containing a large number of slip/shear bands and fewer refined dynamically recrystallized grains were present. The tensile strength increased with the increasing number of passes, but the elongation decreased with the increasing number of passes. The fracture morphologies were also characterised by brittle fractures. After the solid-solution treatment, uniform refined static recrystallized grains were obtained in the three-pass rolled part, while grain growth following static recrystallization occurred in the five-pass rolled part.