双相钢中Si含量对表面氧化物及抑制层形貌的影响

Effects of Si addition in dual phase steels on morphology of surface oxides and inhibition layers in continuous hot-dip galvanizing process

为研究Si含量对双相钢可镀性的影响,对3种不同Si含量的双相钢进行了连续退火镀锌模拟实验。采用SEM和XPS分析表面氧化物和抑制层形貌,结果表明:Si含量的变化对表面氧化物的形貌有较大影响。Si含量从0.04%增加到0.1%,双相钢退火后在晶界处出现Si氧化物的偏析。XPS和EDS证实其为Mn2SiO4。晶内出现的氧化物为MnO和Cr2O3。Si含量增加到0.4%时,Si氧化物在晶界的偏析更加严重,晶界还出现了SiO x。Fe-Al抑制层在Si含量0.04%和0.1%时完整而致密,而Si含量为0.4%时出现了缺陷,这是由于SiO x难以被有效Al还原造成的。

In order to investigate effects of Si contents on galvanizability of dual phase steels, simulated continuous galvanizing processes were conducted for three kinds of dual phase steels with different contents of Si. Then morphology of selective oxides on the annealed steels and Fe-A1 inhibition layers were analyzed by SEM and XPS. The results show that variations of Si content have significant influence on oxides morphology. When Si content increases from 0. 04% to 0. 1%, segregation of Si oxide on surface grain boundaries is obviously observed. XPS and EDS analysis confirms that the Si oxide is MnESiO4. While oxides on grains surface are MnO and Cr203. When Si content is 0.4% , the segregation of Si on grain boundaries becomes severe, and another type of oxide of Si0x appears. The Fe-A1 inhibition layer is moderately compact and uniform when Si contents are 0.04% and 0. 1% , respectively, but defects in Fe-A1 inhibition layer become severe when Si content is 0. 4%. The reason is that the SiOx impedes the growth of Fe-Al inhibition layer.