27SiMn钢等温淬火的TRIP效应

TRIP Effect of the Isothermal Quenching for the 27SiMn Steel

采用拉伸、冲击、硬度等力学性能的测试以及金相组织观察、XRD、SEM分析了27SiMn钢在淬火温度为770～830℃、等温温度为360～420℃和等温时间为10～90min时,显微组织和力学性能的变化规律。结果表明,通过790℃加热保温50min,380℃等温20min,空冷到室温后可以得到铁素体+贝氏体+残余奥氏体的三相组织,得到最好的综合性能,Rm×A5为27 225MPa×%,其中抗拉强度Rm为825MPa,伸长率A5为33%,其冲击韧性和硬度分别为47J/cm2和HB 219。此时残余奥氏体含量为15.76%,贝氏体孕育期最短,TRIP效应最明显。

The micro-structure and mechanical properties of 27SiMn steel was investigated by tensile test, hardness test, impact toughness, metallographic structure, XRD and SEM for quenching in 770--830 ~C, isothermal hold- ing temperature in 360--420 ~C and isothermal holding time in 10--90 min. The results show that 27SiMn can ob- tain of the ferrite, bainite and retained austenite of three-phase organization after heating at 790 ℃ holding 50 rain and isothermal holding at 380℃ for 20 rain. Mechanical properties are 27 225 MPa % of the best overall perform- ance, 825 MPa of the tensile strength, 33% of the elongation, 47J/cm2 and HB219 of the impact toughness and hardness. This residual austenite content is 15.76% and the bainite incubation period is the shortest, which con- tributes to TRIP effect.