Austempering of Hot Rolled Si-Mn TRIP Steels Original Research Article

The austempering after hot rolling in hot rolled Si-Mn TRIP (transformation-induced plasticity) steels was investigated. The mechanism of TRIP was discussed through examination of the microstructure and the mechanical properties of this kind of steel. The results showed that the strain-induced transformation to martensite of retained austenite occurs in hot rolled Si-Mn TRIP steels. The sample exhibited a good combination of ultimate tensile strength and total elongation when it was held at the bainite transformation temperature after hot deformation. The stability of retained austenite increases with an increase in isothermal holding time, and a further increase in the holding duration resulted in the decrease of stability. The mechanical properties were optimal when holding for 25 min, and tensile strength and total elongation reached the maximum values (774 MPa and 33%, respectively).