The Effect of Partitioning Temperature on Residual Austenite and Mechanical Properties of Q&P High Strength Steel during the Continuous Annealing Process

Q&P steel has the advantages of high strength and high elongation, but the key to the production of Q&P steel is the control of heat treatment temperatures, such as the annealing temperature and the partitioning temperature. In this work, SEM, TEM, EBSD, and other methods are used to study the effects of different partitioning temperatures on the microstructure and properties of 2.0 Mn low-carbon Q&P steel during the continuous annealing process. The results show that the grain size and quantity of the residual austenite (RA) increase significantly with the increase in the partitioning temperature, and the strength of the machine can reach 27.2 GPa% at the partitioning temperature of 370 °C. Meanwhile, the retention mechanism of the residual austenite at the partitioning stage is also clarified.