| 【文章摘要】 The effects of annealing time and temperature on the retained austenite content and mechanical properties of 0.2C-7Mn steel were studied.The retained austenite content of 0.2C-7Mn steel was compared with that of 0.2C-5Mn steel.It is found that 0.2C-7Mn steel exhibits a similar variation trend of retained austenite content as 0.2C-5Mn steel.However,in detail,these trends are different.0.2C-7Mn steel contains approximately 7.5vol%retained austenite after austenitization and quenching.The stability of the reversed austenite in 0.2C-7Mn steel is lower than that in 0.2C-5Mn steel;in contrast,the equilibrium reversed austenite fraction of 0.2C-7Mn steel is substantially greater than that of 0.2C-5Mn steel.Therefore,the retained austenite content in 0.2C-7Mn steel reaches 53.1vol%.The tensile results show that long annealing time and high annealing temperature may not favor the enhancement of mechanical properties of 0.2C-7Mn steel.The effect of retained austenite on the tensile strength of the steel depends on the content of retained austenite;in contrast,the 0.2%yield strength linearly decreases with increasing retained austenite content. |