Abstract In this article, the influence of electrode tip diameter is investigated for spot welded duplex stainless steel (DSS). Electrode tip diameter and welding current are considered as the major influencing parameters and their values are varied within the feasible range, suitable for 0.8 mm thick sheet, whereas other important parameters such as welding time and electrode force are kept constant. DSS with the chosen thickness range is now becoming a useful material in automotive body-in-white applications and in future it will become one of the key materials replacing the existing materials and hence research outcome of the present work may be beneficial from application view point. In this work, the spot welding quality is inspected through metallurgical aspects (microstructure and microhardness), physical aspects (nugget diameter and electrode indentation), mechanical performance (tensile shear strength [TSS]) and failure mode. The obtained result shows that smaller electrode tip diameter limits nugget diameter due to expulsion phenomena and increases electrode indentation due to higher current intensity. TSS decreases with increase in electrode tip diameter for the same welding current but maximum TSS obtained for particular electrode tip diameter increases with increase in electrode tip diameter up to a specific limit and then it remains constant.

中文翻译：

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电极尖端直径对点焊双相不锈钢冶金和机械方面的影响

摘要 本文研究了点焊双相不锈钢（DSS）电极尖端直径的影响。电极尖端直径和焊接电流被认为是主要的影响参数，它们的值在可行范围内变化，适用于0.8mm厚的板材，而其他重要参数如焊接时间和电极力保持不变。具有所选厚度范围的 DSS 现在正在成为汽车白车身应用中的有用材料，未来它将成为替代现有材料的关键材料之一，因此从应用的角度来看，当前工作的研究成果可能是有益的. 在这项工作中，通过金相方面（显微组织和显微硬度）检查点焊质量，物理方面（熔核直径和电极压痕）、机械性能（拉伸剪切强度 [TSS]）和失效模式。所得结果表明，较小的电极尖端直径会因排斥现象而限制熔核直径，并会因较高的电流强度而增加电极压痕。对于相同的焊接电流，TSS 随着电极尖端直径的增加而减小，但对于特定电极尖端直径获得的最大 TSS 会随着电极尖端直径的增加而增加，直至达到特定限制，然后保持恒定。