不同Mg含量铝锌镁产品镀层组织与耐蚀性研究  

Microstructure and corrosion resistance investigation of the Al-Zn-Mg coated products with different Mg contents

作　　者：徐呈亮 刘武华[2] 胡燕慧 刘华赛 韩赟 滕华湘 XU Chengliang;LIU Wuhua;HU Yanhui;LIU Huasai;HAN Yun;TENG Huaxiang(Technology Institute of Shougang Group Co.,Ltd.,Beijing 100043,China;Shougang Jingtang United Iron and Steel Co.,Ltd.,Tangshan 063200,China)

机构地区：[1]首钢集团有限公司技术研究院,北京100043 [2]首钢京唐钢铁联合有限责任公司,河北唐山063200

出　　处：《轧钢》2023年第4期43-51,共9页Steel Rolling

基　　金：河北省重点研发计划资助项目(20311004D)。

摘　　要：针对热浸镀铝锌镁镀层产品(55%Al-Zn-1.6%Si-(0~3)%Mg)中不同Mg含量的镀层组织与耐蚀性进行了研究,旨在解决此类产品加工和使用过程中的表面缺陷,主要包括镀层组织不均、耐蚀性偏低、镀层表面捂水发黑等质量问题。采用扫描电镜(SEM)、X射线衍射(XRD)、辉光分析(GDS)、三维形貌测试、电化学测试等方法,对不同Mg含量镀铝锌产品进行了实验测定,发现Mg含量不同是造成镀层组织形貌、耐蚀性差异的重要原因,在一定范围内提高Mg含量有利于镀层组织均匀性及耐蚀性能的提升。对于镀层表面捂水发黑质量问题,镀层组织均匀性和表面钝化工艺共同决定此类缺陷的发生率。最后,通过热力学计算,探讨了添加微量Ti或B对控制铝锌镁晶粒尺寸的可行性,即添加Ti或B之后形成的TiAl_(3)相、AlB_(2)相有利于提高凝固组织的形核率,从而起到细化凝固组织的作用。The microstructures and corrosion resistance of the hot-dip 55%Al-Zn-1.6%Si-(0~3)%Mg galvanized products were studied,aiming at solving the surface defects problems such as non-uniformity of the microstructures,low level of corrosion resistance and the water-induced blackening of the coating during the manufacturing and utilization process.The experimental measurements of the Al-Zn-Mg coated products with different Mg contents were conducted by means of scanning electron microscopy(SEM),X-ray diffraction method(XRD),glow discharge emission spectrometry(GDS),3D surface topography measurement and electrochemical test.It is discovered that the varied Mg contents should be the main reason of the different microstructures and corrosion resistances,and the proper elevation of Mg content will contribute to the homogenization of the microst ructures of coating the microstructures and the increase of corrosion resistances.In terms of the water-induced blackening of the Al-Zn-Mg coating,it is noticed that the homogenization of the microstructures of coating and the passivation technology may influence the incidence rate of such defects.Finally,the addition of trace amount of Ti or B to control the grain size of the Al-Zn-Mg coating was discussed by means of thermodynamic calculations.It is found that with trace amount of Ti or B,the precipitated TiAl_(3) or AlB_(2) will benefit the nucleation rates of the solidified microstructures,which will contribute to refine the grain size of the Al-Zn-Mg coated products.

关 键 词：铝锌镁镀层 凝固组织 耐蚀性 镀层发黑 微量Ti/B 

分 类 号：TG174.4[金属学及工艺—金属表面处理]