Annealing processing parameters and microstructure evolution of hot-rolled low-carbon medium-manganese TRIP steels

The effects of annealing processing on the mechanical properties and microstructure evolution of high strength and high ductility TRIP steels were investigated.The hot-rolled-and-annealed TRIP steel has remarkable strength and ductility due to the prior martensitic microstructure obtained in the as-hot-rolled condition and the retained austenite formed during intercritical annealing.The results show that the test steels have a tensile strength of over 1 000 MPa and an elongation of over 30%,and the product of ultimate tensile strength and total elongation exceeds 30 GPa·%.The mechanical properties are significantly influenced by intercritical annealing temperature and soaking time.When the TRIP steel is treated at an intercritical annealing temperature of 630℃ for 18h,the best mechanical properties are obtained.