Effects of rolling temperature on the microstructure and mechanical properties of Ti-Mo microalloyed hot-rolled high strength steel

The effects of rolling condition on the microstructure and mechanical properties of Ti-Mo microalloyed hot-rolled high strength steel were investigated by varying rolling temperature from austenite recrystallization region to austenite+ferrite dual phase region. The results revealed that rolling temperature plays a decisive role in the mechanical properties by significantly affecting the characteristics of grain refinement and precipitation. Conducting the rolling in the regions through austenite recrystallization region to austenite non-recrystallization region was able to provide desirable microstructural features for impact properties as well as for strength by inducing a homogeneous and fine grain structure, well developed dislocation structures inside grain, and relatively high number density of fine carbides, although precipitation hardening effect was somewhat reduced by strain-induced precipitation.