60Si2Mn弹簧钢常温发黑工艺

Blackening of 60Si2Mn spring steel at room temperature

通过正交试验对60Si2Mn弹簧钢的常温发黑工艺进行优化,得到的最优溶液组成和工艺条件为:五水合硫酸铜5 g/L,铬酸酐3.5 g/L,氯化氨4.5 g/L,SY-31发黑添加剂200 mL/L,pH 2.0,温度25℃,时间4 min.在最优条件下所得膜层均匀、致密,在室温的20%硫酸铜溶液中浸泡20 s后无红色斑点形成,能通过48 h中性盐雾试验.

The process for blackening 60Si2Mn spring steel was optimized by orthogonal test.The optimal bath composition and conditions are as follows:copper sulfate pentahydrate 5 g/L,chromic anhydride 3.5 g/L,ammonia chloride 4.5 g/L,SY-31 blackening agent 200 mL/L,pH 2.0,temperature 25℃,and time 4 min.The film obtained under the optimized conditions was uniform and compact.No red spot was formed on it after being immersed in 20%copper sulfate solution at room temperature for 20 seconds,and it passed a 48-hour neutral salt spray test.