Influence of Al Additions on Austenite Decomposition in Continuously Annealed Dual-Phase Steels

摘要

Recent advances in the development and successful implementation of Al-alloyed TRIP steels make it reasonable to investigate if a similar approach may be beneficial for manufacturing dual-phase (DP) steels. It is known that austenite formation and its decomposition control the final microstructure and therefore the final mechanical properties. The purpose of this work was to study, using dilatometry and continuous annealing simulations, the effect of aluminium in the range from 0.04 to 1.1 percent on the formation of austenite and its subsequent decomposition during continuous cooling. It has been observed that an increase in Al content increases the stability of austenite and expands the window of the annealing parameters where a dual-phase structure can be obtained using relatively low cooling rates. The relationship between Al content, annealing parameters and structure/properties is discussed.