ABSTRACT Intermetallic formation by solute segregation during dissimilar welding of Inconel 718 and SS316L stainless steel poses a severe challenge of solidification cracking in the welded structure. The minimisation of these intermetallic phases and, eventually, the solidification cracks through variation in welding speed is undertaken in the current study. With a reduction in welding speed, an improvement in the weld dilution level is observed along with a change in microstructural morphology from columnar to equiaxed dendrites. A reduction in solute segregation is evident with higher weld dilution level and equiaxed structure as compared with the columnar dendrites. The enrichment of Nb, Mo, and Ti is witnessed near micro-crack sites produced with a higher welding speed. X-ray diffraction (XRD) analysis confirmed the presence of various intermetallic phases and found to decrease with a reduction in the welding speed. With a reduction in welding speed, the tensile strength improved marginally, whereas a remarkable improvement in tensile ductility (∼ 90%) was found.

中文翻译：

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Inconel 718 和奥氏体不锈钢异种焊接中微裂纹的缓解

摘要 Inconel 718 和 SS316L 不锈钢异种焊接过程中通过溶质偏析形成金属间化合物对焊接结构中的凝固裂纹提出了严峻挑战。在当前的研究中，通过改变焊接速度来最大限度地减少这些金属间相，并最终减少凝固裂纹。随着焊接速度的降低，观察到焊接稀释水平的改善以及微观结构形态从柱状到等轴枝晶的变化。与柱状枝晶相比，更高的焊缝稀释水平和等轴结构明显减少了溶质偏析。Nb、Mo 和 Ti 的富集在以较高焊接速度产生的微裂纹位置附近可见。X 射线衍射 (XRD) 分析证实了各种金属间相的存在，并发现随着焊接速度的降低而减少。随着焊接速度的降低，拉伸强度略有提高，而拉伸延展性显着提高（约 90%）。