ABSTRACT Advanced high strength steels are usually coated by a zinc layer for an increased resistance against corrosion. During the resistance spot welding of zinc coated steel grades, liquid metal embrittlement (LME) may occur. As a result, cracking inside and around the spot weld indentation is observable. The extent of LME cracks is influenced by a variety of different factors. In this study, the impact of the used electrode geometry is investigated over a stepwise varied weld time. A spot welding finite element simulation is used to analyse and explain the observed effects. Results show significant differences especially for highly increased weld times. Based on identical overall dimensions, electrode geometries with a larger working plane allow for longer weld times, while still preventing LME within the investigated material and maintaining accessibility.

中文翻译：

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通过调整电极几何形状防止电阻点焊中的液态金属脆化裂纹

摘要 高级高强度钢通常涂有一层锌层，以提高抗腐蚀性。在镀锌钢种的电阻点焊过程中，可能会发生液态金属脆化 (LME)。结果，可以观察到点焊压痕内部和周围的裂纹。LME 裂缝的程度受多种不同因素的影响。在这项研究中，所使用的电极几何形状对逐步变化的焊接时间的影响进行了研究。点焊有限元模拟用于分析和解释观察到的效果。结果显示出显着差异，尤其是焊接时间大幅增加的情况。基于相同的总体尺寸，具有更大工作平面的电极几何形状允许更长的焊接时间，