淬火温度对NM400马氏体耐磨钢残余应力的影响

EFFECT OF QUENCHING TEMPERATUR ON RESIDUAL STRESS OF NM400 MARTENSITIC WEAR-RESISTANCE STEEL

采用热处理实验、X射线衍射(XRD)、光学显微镜(OM)、扫描电镜观察(SEM)等方法,研究了不同淬火温度对NM400马氏体耐磨钢的组织、硬度与表面残余应力的影响规律。结果表明,随着淬火温度的升高,原始奥氏体逐渐均匀化并粗化长大,实验钢表面轧制方向的残余应力逐渐增大。淬火温度940℃以下,随着温度升高,马氏体板条束逐渐增多,板条块逐渐减少,实验钢硬度随淬火温度的升高而增加;淬火温度1150℃时,马氏体板条块增多,马氏体板条粗化,表面硬度明显下降。

In this investigation,heat treatment experiment,X-ray diffraction(XRD),optical microscope(OM),scanning electron microscope(SEM)were used to study the effect of different quenching temperatures on the microstructure,hardness and surface residual stress of NM400 martensitic wear resistant steel.The results show that with the increasing of quenching temperature,the original austenite appeared uniform and coarsened,and the residual stress in the rolling direction of the test steel increased gradually.Moreover,with the increasing of the quenching temperature(below 940℃),the amount of martensitic packets increased,and the amount of martensitic block decreased.However,when the quenching temperature increased to 1150℃,the amount of martensitic block increased,and the hardness decreased obviously due to the coarsening of martensitic plates and the size of original austenite.The results of this study provide guidance for the determination of heat treatment in the production of martensitic wear-resistant steel.