Study on microstructure and texture of high-strength plastic cold-rolled dual-phase DP980 steel

Abstract

In order to improve the strength and plasticity of cold-rolled dual-phase DP980 steel, the relationship between process structure and properties were systematically studied by adjusting continuous annealing process parameters. The microstructure, recrystallized grains, phase distribution, and texture of different phases at different annealing temperatures were analyzed by OM, SEM, and EBSD. At the same time, the effect of continuous annealing temperature on the strength and plasticity were studied by mechanical tensile tests. The results obtained show that by optimizing and adjusting the continuous annealing process, not only a small amount of residual austenite can be obtained on the structure of cold rolled ferrite and martensite dual phase steel, but also recrystallized grains can be refined. Finally, cold-rolled DP980 steel with YS/TS < 0.5 and high elongation A50 < 15% can be obtained, and its strength/plasticity balance can be increased to 15-20 GPa%, which is also favorable for its formability.