Synergistic enhancement of strength and ductility through the combination of heavy warm rolling and quenching & partitioning

Abstract

A combined warm rolling and quenching–partitioning (WR-Q&P) process was applied to a low-carbon martensitic stainless steel and compared with conventional warm rolling (WR) and quenching–partitioning (Q&P) treatments. The introduction of a high dislocation density through warm rolling facilitated carbon partitioning during subsequent processing, leading to microstructural refinement and the stabilization of ultrafine retained austenite (6.1%) with a uniform distribution. The WR-Q&P sample exhibited a significantly enhanced yield strength (1000.4 MPa), ultimate tensile strength (1290.5 MPa), and uniform elongation (5.8%) relative to the Q&P-treated steel. The improvement in mechanical properties was primarily attributed to dislocation and grain boundary strengthening mechanisms, while the enhanced ductility resulted from the increased volume fraction and homogeneous dispersion of retained austenite.