锌浴中钛对含硅钢Fe-Zn反应的抑制作用

Controlling Fe-Zn reaction of Si-containing steels with adding titanium in zinc bath

选用Q235和Q345钢,在纯锌浴和含钛量分别为0.05%、0.10%、0.15%、0.20%(质量分数)的合金浴中浸镀0.5、1、3、5、8 min。利用扫描电子显微镜和能谱仪研究了钛对热浸镀锌组织和生长动力学的影响,并提出钛对含硅钢铁锌反应抑制作用的机理。结果表明:钛的加入缩短了Γ的孕育期,促进了合金层中δ的生长和ζ的消失,δ的生长依然受扩散控制,呈抛物线生长规律;Zn-0.05%Ti锌浴可以很好的抑制高硅钢的硅反应性;含硅钢热浸镀锌钛合金浴时,在锌浴中会形成锌铁钛三元T相,该相能吸收ζ晶界处富集的硅,从而抑制了铁锌反应。

Both Q235 and Q345 steels were immersed for 0.5 to 8 min in Zn bath with different amount of Ti, ranging from 0 to 0.20 mass% , for galvanization. The effect of Ti in Zn bath on microstructure and growth kinetics of hot-dip galvanizing coatings on the two steels were investigated by means of SEM and EDS analysis. Base on the experiment, the mechanism of Ti additions in controlling Fe-Zn reaction was proposed. The results show that addition of Ti in the zinc bath decreases the incubation time of F phase, promotes the growth of phase and accelerates the disappearance of phase, and the growth-rate time constant is still less than 0. 5 which indicates parabolic diffusion controlled growth. The Zn-0. 05% Ti bath can control silicon reactivity of high Si-containing steels. The ternary phase T forms at the interface of phase and liquid, which can absorb Si accumulated at the boundary of phase and control the Fe-Zn reaction.