采用红外光谱分析、扫描电镜及能谱分析等方法,对热镀铝锌钢板表面锌花尺寸不均匀的原因进行分析。结果表明:锌花尺寸不均匀是钢基板铁元素的溶解差异引起的;浸镀时,正常钢基板表层溶解了足够量的铁元素,过饱和的铁元素限制了铝枝晶的形核速率,同时促进了硅元素的分配,共晶析出的硅针少,外覆层凝固时铝枝晶的形核数量少,长大成正常的大锌花;表面带有羧酸铁的基板,板面浸润性差,铁元素的溶解量少,铝枝晶的形核不受限制,生成了小锌花。

The causes of uneven size of spangle on the surface of hot dip Al-Zn steel sheet were analyzed by means of infrared spectrum analysis, scanning electron microscope and energy spectrum analysis. The results show that the uneven size of spangle was caused by the difference of iron dissolution in the steel substrate. During immersion plating, a sufficient amount of iron element was dissolved in the surface layer of the normal steel substrate. The supersaturated iron element limited the nucleation rate of aluminum dendrites, and promoted the distribution of silicon element, there were fewer silicon needles precipitated from eutectic. When the outer coating was solidified, the aluminum dendrites had fewer nuclei, and grew into normal large spangles. The substrate with iron carboxylate on the surface had poor wettability, less iron dissolution, unrestricted nucleation of aluminum dendrites and small spangles were formed.