Effect of processing parameters on the evolution of dislocation density and sub-grain size of a 12%Cr heat resistant steel during creep at 650 °C

▶ Dislocation density/subgrain size evolution in 12%Cr steel studied by HAADF-STEM. ▶ Correlation processing parameters/microstructure evolution/creep curves was studied. ▶ Hot-forged samples present higher dislocation density than non hot-forged samples. ▶ Crept samples showed increase of subgrain size and reduction of dislocation density. ▶ Hot-forging enhances creep-strength due to better particle size and distribution.