立柱热镀锌层剥落原因分析和改进

Cause analysis on peeling of hot-dip zinc coating from guardrail post and countermeasures

某热浸镀锌立柱在冲孔后镀层出现起皱和脱落现象。采用扫描电镜和能谱仪分析立柱不同部位热浸镀锌层的组织结构,发现锌层中脆性ζ相过厚是主要原因,通过适当缩短浸镀时间和在浸镀液中添加0.1%(质量分数)的Al可解决上述问题。

The wrinkling and peeling phenomena appeared on hot-dip zinc coating of guardrail posts after being punched.The phase structure of hot-dip zinc coating at different positions of guardrail post was analyzed by scanning electron microscopy and energy-dispersive spectroscopy.It was found that the excessive thickness of brittle ζ-phase layer in zinc coating was the primary cause to the said defects.The problem could be solved by appropriately shortening the dipping time and adding 0.1%(mass fraction)of aluminum to the zinc bath.