热镀锌板表面锌层起泡原因探讨

Analysis of Surface Blister of Hot-dip Galvanized Steel

热镀锌板在冲压成零件时,局部的镀锌层出现约3mm大小的起泡,将起泡用手术刀切开,撕下锌层,采用扫描电镜对起泡部位的基体以及锌层靠基体的表面进行了分析,对比分析正常部位纯锌层与基体之间的抑制层。结果表明:正常部位的抑制层为细小弥散分布的Fe2Al5颗粒,产生起泡的缺陷部位未见到抑制层颗粒,锌层与基板之间存在局部聚集的Al2O3夹渣,冲压成型后,夹渣松动,锌层与基板分离,导致锌层起泡。

Surface blister emerges on hot-dip galvanized steel sheet when it is stamped to automobile parts.The blister is cut by scalpel and the internal morphology behind the Zinc layer is exposed.Both the blister and the normal parts are studied by scanning electron microscopy（SEM）.It shows that small particles uniformity distributing on inhibition layer in normal parts is identified as Fe2Al5.However,no Fe2Al5 particles are found near blister.Slag inclusions like Al2O3 appear in the blister parts.The result indicates that the slag inclusions are loose and the zinc layer is separated from steel substrate,which leads to the formation of the surface blister.