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基于中心复合试验设计方法,采用热丝脉冲TIG(tungsten inert gas arc welding)工艺,在AISI 4130基体上堆焊Inconel 625合金层。借助响应面法建立了焊缝几何特征与工艺参数之间的数学模型。根据优化后的工艺参数,获得了平坦、连续、无缺陷的多道两层堆焊层。堆焊层微观组织主要由柱状晶组成,在融合界面附近存在少量的平面晶与胞状晶,其顶部组织为等轴晶与转向晶。利用动态极化曲线法对基体与堆焊层的耐腐蚀性能进行了评价。结果表明:堆焊层的耐腐蚀性随着Fe含量的增加而降低,但增加堆焊层的层数可以显著提高耐腐蚀性能。而且,两层堆焊层试样与铸态Inconel 625的耐腐蚀性能基本相当。
Based on the center composite test design method, the Inconel 625 alloy layer is deposited on the AISI 4130 substrate by using a tungsten inert gas arc welding (TIG) process. With the help of response surface method, the mathematical model between the geometrical characteristics of welding seam and the process parameters was established. According to the optimized process parameters, a flat, continuous and defect-free multi-track two-layer surfacing layer was obtained. The microstructure of surfacing layer mainly consists of columnar crystals. There are a few flat crystals and cellular crystals in the vicinity of the fusion interface. The top of the surfacing layer is equiaxed and transitional. The corrosion resistance of matrix and surfacing layer was evaluated by dynamic polarization curve method. The results show that the corrosion resistance of the overlay decreases with the increase of Fe content, but increasing the number of overlay layers can significantly improve the corrosion resistance. Furthermore, the corrosion resistance of the two-layer overlay specimen and the as-cast Inconel 625 is comparable.