The present work addresses the weldability of dissimilar materials Inconel 718 and AISI 316L stainless steel through metallurgical and mechanical characterization of the joint. The 3D heat transfer model analyzes the solidification behavior for a pulsed arc energy source. However, intermetallic formation deteriorates the welded joint properties and promotes solidification cracking in the weld zone. We attempt to join these dissimilar materials without using any filler materials and allowing solidification with the use of a pulse current. The use of a pulse current during microplasma arc welding assists in the formation of a beneficial microstructure that produces strong welds. Since the solidification parameters (G·R and G/R) largely define the weld microstructure, their effect on the weld joint properties is investigated herein. With an increase in the pulse current, the (G/R) decreases and enables the formation of an equiaxed solidified structure in the weld zone. A reduction in the amount of various intermetallic phases is observed in the equiaxed regions compared to amount present in areas with a columnar structure. The tensile strength of the joint is superior to that of AISI 316L stainless steel, and failure is observed in the heat-affected zone of this material. The best joint efficiency herein of 108 pct and elongation of 35.3 pct is achieved for the welding condition having the lowest (G/R) value. An improvement in the elongation is achieved for the weld joint with a reduction in the (G/R) value.

本工作通过接头的冶金和机械特性解决了异种材料Inconel 718和AISI 316L不锈钢的可焊性。3D传热模型分析了脉冲电弧能源的凝固行为。然而，金属间化合物的形成降低了焊接接头的性能并促进了焊接区的凝固裂纹。我们尝试在不使用任何填充材料的情况下结合这些异种材料，并使用脉冲电流进行固化。在微等离子体弧焊期间使用脉冲电流有助于形成可产生牢固焊接的有益微结构。由于凝固参数（G · R和G / R）在很大程度上定义了焊缝的微观结构，本文研究了它们对焊缝性能的影响。随着脉冲电流的增加，（G / R）降低，并能够在焊接区中形成等轴凝固组织。与在具有柱状结构的区域中存在的量相比，在等轴区域中观察到各种金属间相的量减少。接头的抗拉强度优于AISI 316L不锈钢，并且在该材料的热影响区观察到破坏。对于具有最低（G / R）的焊接条件，此处可获得108 pct的最佳接合效率和35.3 pct的延伸率）值。通过减小（G / R）值，可以提高焊接接头的延伸率。