Effect of TMCP on Microstructure and Mechanical Properties of 304 Stainless Steel

The present study investigates the evolution of microstructure and mechanical properties of 304 stainless steel after thermo‐mechanical controlled processing (TMCP). Three different FRTs (finish rolling temperatures) have been adopted and the micro‐constituents are identified as austenite grains, stacking faults, annealing, and deformation twins. Fine austenite grains in the range of 1–30 μm are obtained at lower FRT (700 °C) whereas at higher FRT, coarse grains are formed. TEM and X‐ray analyses indicate the formation of M 23 C 6 ((Cr, Fe) 23 C 6 ) precipitates for higher FRT (900 °C). Specimen processed with 700 °C FRT results into 37% enhancement in UTS compared to the base metal which is attributed to fine partially recrystallized grain, extensive deformation twinning and high dislocation density. Maximum elongation (68%) is obtained due to the formation of strain‐free equiaxed grains (≈40 μm) at 900 °C FRT.