热丝脉冲TIG堆焊Inconel625成型质量优化与性能

Formation quality optimization and performance of INCONEL 625 cladding using hot-wire pulsed TIG

摘要:

基于中心复合试验设计方法，采用热丝脉冲TIG工艺在AISI 4130基体上堆焊Inconel 625合金。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。

Abstract:

Based on the central composite rotatable design (CCD), clad beads of Inconel 625 were deposited on the surface of AISI 4130 plates using hot wire pulsed TIG technology. The response surface methodology (RSM) was utilized to establish models between process parameters and geometrical characteristics of the clad beads. Then, multiple-track two-layer weld overlay was successfully deposited using the optimized process parameters. The microstructure of the weld overlay is primarily composed of columnar dendrites, and there are also a few planar crystals and cellular dendrites situated near the fusion zone. Meanwhile, equiaxed grains and steering dendrites are mainly distributed in the upper portion of the weld overlay. Potentiodynamic polarization tests were used to evaluate the corrosion resistance of the weld overlay and substrate. The results show that adding clad layers can enhance the corrosion resistance, which degrades with the increase in Fe dilution. Moreover, the corrosion resistance of the second layer surface is close to that of wrought Inconel 625.