退火工艺及形变对含铌TRIP800钢显微组织和力学性能的影响

Effect of Annealing Process and Deformation on Microstructure and Mechanical Properties of TRIP800 Steel with Nb

采用静态拉伸试验、定量彩色金相和X射线衍射等方法,研究了含铌TRIP800钢的微观组织和力学性能,采用EBSD分析了形变量对残奥体积分数的影响规律。结果表明,在两相区加热温度为800℃、400℃贝氏体区等温条件下,含铌TRIP800钢的显微组织中残留奥氏体量约为12%,强塑积最高可达22.185GPa·%;随着形变量增大,残奥体积分数减小,塑性变形初期残奥转变比率最大。

The microstructure and mechanical properties of TRIP800 steel with Nb were researched by static tension, quantificational color metallograph and X-ray diffractometer. And the influence regularity of strain on volume fraction of retained austenite was analysed by EBSD. The results show that, about 12% retained austenite can be obtained in the microstructure of TRIP800 steel with Nb on the conditions of subcritical heating temperature of 800 ℃ and the isothermal temperature of bainite region of 400 ℃, and the maximum value of the specimens＇ strength and ductility product can be up to 22.185 GPa·%. With the increase of strain, the volume fraction of retained austenite decreases, and the transformation ratio of retained austenite is maximum at the early stage of plastic deformation.