材料期刊网

The effect of thermomechanical control processing (TMCP) on microstructure and mechanical properties of Fe-0.2C-1.44Si-1.32Mn hot-rolled TRIP steel was investigated by experiment. Strain-induced transformation and transformation-induced plasticity behavior of retained austenite was discussed. The results show that using multi-pass deformation, reduction per pass of more than critical deformation in austenite recrystallization region, total reduction of more than 58 pct in non-recrystallization region and in high temperature section of two-phase region can result in austenite being refined before γ → α transformation. It is beneficial to get refined ferrite grain in final microstructure. To obtain fine and uniform microstructure and excellent strength-ductility balance, a three-step cooling process (Laminar Cooling－Air Cooling－Ultra-Fast Cooling) after hot rolling was conducted. The ultimate tensile strength and elongation of the testing steel can reach 663 MPa and 41 pct respectively.