淬火温度对含铜5Cr15MoV马氏体不锈钢性能的影响

将含铜5Cr15MoV马氏体不锈钢在不同温度热处理并使用光学显微镜(OM)、扫描电子显微镜(SEM)、X射线衍射(XRD)、透射电子显微镜(TEM)、硬度测试和电化学测试等手段对其表征，研究了淬火温度对其组织、硬度以及耐蚀性能的影响。结果表明，铜元素的添加提高了材料中残余奥氏体的体积分数，而使其硬度降低。淬火后钢中的未溶碳化物为fcc结构的富铬M₂₃C₆型碳化物，铜元素的添加对5Cr15MoV马氏体不锈钢中碳化物的尺寸和形貌没有明显的影响，但是使其耐蚀性能略微降低。随着淬火温度从1000℃提高到1100℃，未溶碳化物逐渐减少，耐蚀性提高。残余奥氏体的含量也随着淬火温度的提高而增多，碳化物与残余奥氏体的共同作用使淬火后钢的硬度曲线呈抛物线状并在1050℃达到最大值。

Effect of Quenching Temperature on Microstructure and Properties of Cu-bearing 5Cr15MoV Martensitic Stainless Steel

The Cu-bearing martensitic stainless steel 5Cr15MoV was heat treated at different temperatures for 30 min and then oil quenched. The effect of quenching temperature on the microstructure, hardness and corrosion resistance of the steel were investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), hardness tester and electrochemical test. The results show that the addition of Cu increases the volume fraction of residual austenite and decreases the hardness of the steel, the undissolved carbides in the quenched steel are Cr rich M₂₃C₆ type carbides with FCC structure, and the addition of Cu has no obvious effect on the size and morphology of the carbides in the 5Cr15MoV martensitic stainless steel, but its corrosion resistance is slightly reduced. With increase of the quenching temperature from 1000^oC to 1100^oC the undissolved carbides decrease, while the corrosion resistance of the steel increases. Meanwhile, the content of residual austenite also increases with the increase of quenching temperature. The combined action of carbide and residual austenite makes the hardness versus temperature curve of the quenched steel a parabolic shape with a maximum value at 1050°C.