65Mn高弹性垫片的机械镀锌研究

目的克服65Mn高弹性垫片电镀锌产生的氢脆问题。方法采用机械镀锌方法在65Mn高弹性垫片表面制备了镀锌层,采用目测法观察镀层的外观及镀层完整情况,采用硫酸铜试验分析镀层厚度的均匀性,采用划格试验法测试镀层的结合强度,采用铁试剂方法检测镀层的孔隙率,通过预紧固检测分析了镀液p H值对镀后垫片氢脆的影响,采用中性盐雾实验法检测了钝化对镀层耐蚀性能的影响。结果制备的机械镀锌层表面平滑,覆盖完整,无起皮、漏镀等缺陷。镀层呈灰亮色,厚度均匀,具有足够的致密度。当镀液环境的p H值较低时(1~2和2~3),施镀过程造成一定程度的氢脆隐患;镀液环境的p H值为3~4时,机械镀锌垫片不会发生裂纹或断裂。结论施镀时,镀液环境的p H值调整为3~4,或垫片在镀锌后装配前自然放置1~2周,采用机械镀锌的方法可消除65Mn高弹性垫片镀锌过程中的氢脆现象。钝化处理可推迟或防止65Mn高弹性垫片机械镀锌层白锈的产生。

Mechanical Galvanizing of 65Mn High Elastic Washer

To solve the problem of hydrogen embrittlement of 65Mn high elastic washer. In this paper, Zinc coating was prepared on the surface of 65Mn high elastic washer by mechanical plating. The appearance/integrity, bonding strength and porosity of the coating were characterized by visual inspection, grid test and ferroxyl text respectively. The uniformity of the coating thickness was ana-lyzed by copper sulfate test. The effect of pH value of the plating solution on the hydrogen embrittlement of the plated washer was analyzed by means of pre-fastening test and the effect of passivation on corrosion resistance of the coating was investigated by neutral salt spray test. The surface of the prepared zinc coating is smooth, the cover is complete, and there are no defects such as peeling, leakage, and so on. The coating is light grayish tone, the thickness of the coating is uniform, and the coating has enough density. When the pH value of the plating solution is lower (1~2 and 2~3), the hydrogen embrittlement was caused in plating process. When the pH value of the plating solution is 3~4, no cracks or cracks has been found. The passivated mechanical plated zinc coating of high elastic washer shows good corrosion resistance after 96 h of NSS test. when the pH value of the plating solution could be set to 3~4, or the mechanically deposited washers could be natural aged at least for 1 to 2 weeks, using the method of mechanical plating can effectively eliminate hydrogen embrittlement of 65Mn high elastic pad plating process. Passivation treatment could delay or prevent the formation of white rust in the surface of mechanical zinc coating.