Influence of Finish Rolling Temperature on Microstructure and Mechanical Properties of a 19Cr1.5Mo0.5W Ferritic Stainless Steel

A 444-type heat-resistant ferritic stainless steel containing 0.05 wt% Ce (rare earth element) and 2 wt% (Mo + W) was adopted as an experimental material to study the effect of finish rolling temperature on microstructure and texture evolution as well as on mechanical properties and formability. The rolling processes contain hot rolling at two different finish rolling temperatures (860 °C and 770 °C) and annealing, cold rolling and subsequent annealing. It was found that the microstructures after hot rolling and annealing could be refined by lowering finish rolling temperature. The resultant microstructures after cold rolling and annealing were hereditarily refined. Lowering finish rolling temperature can weaken α-fiber texture in hot-rolled or cold-rolled ferritic stainless steel strip, while γ-fiber texture in the final product was homogeneously strengthened. Additionally, enhanced mechanical property and formability in terms of strength and average plastic strain ratio could be obtained via decreasing finish rolling temperature.