摘要： 针对汽车用热镀锌板在涂装生产线前处理工序过程中出现的白点问题，研究了脱脂水洗、表调、磷化等各工序阶段镀锌板的外观形貌，并进行了微区成分分析。 实验发现：由于热镀锌在其生产成型过程中产生的锌层脱落、翘起、划伤、裂纹等缺陷，导致其在涂装前处理时易受前处理试剂及水质等因素的影响，从而在高温高湿的环境下产生表面的腐蚀性缺陷，形成白点。 为克服这些缺陷，本文提出了一些相应的整改措施。

关键词: 热镀锌板, 前处理, 白点

Abstract: The defect such as lemon spot occurred on the surface of pretreated hot galvanized steel sheet for automotive substrate has been analyzed via an examination of its surface morphology dunng different pretreating steps including degreasing, water washing, surface modification and phosphatization etc in addition, the components and microstructuresin the defect areas are determined. The results show that the hot dip galvanized steel sheet is easily affected by pretreating agents and water during pretreatment due to defects including peeling, scrub and crack, etc. occurred on surface of zinc layers during molding process, which result in lemon spots on the conditions of high temperature and humidity. Thus, some solutions hereto have been put forth accordingly.

Key words: hot dip galvanized, pretreatment, lemon spot