材料：优质合金钢                                 热处理
        (1) 38CrMoAlA (JIS SACM645)        渗氮处理
        (2) 42CrMo (AISI 4140)                   电镀硬铬层
                                                               高频淬火
                                                               喷涂双金属合金层
                                                               真空淬火