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采用中频点焊机对1.6 mm厚BR1500HS热成形钢点焊性能进行研究,对焊接工艺参数对点焊接头力学性能和组织的影响进行了分析。结果表明,点焊熔核尺寸随焊接电流和焊接时间增加而增大,熔核区组织为板条马氏体,粗晶区为粗大马氏体+少量M-A岛元,细晶区为细小的马氏体。随着焊接时间的延长,点焊接头承受拉剪载荷的能力增加,承受正拉载荷能力降低,接头疲劳寿命明显降低;热成形钢点焊接头热影响区有明显的软化,随着焊接时间延长,热影响区软化程度有所增加。
The spot welding performance of BR1500HS thermoformed steel with 1.6 mm thickness was studied by IF welder. The influence of welding parameters on the mechanical properties and microstructure of spot welded joints was analyzed. The results show that the size of spot weld nugget increases with the increase of welding current and welding time. The nugget zone is lath martensite, the coarse grain zone is coarse martensite + a little MA island, and the fine grain zone is small Martensite. With the extension of welding time, the ability of the spot welded joint to bear the tensile load increases, the ability to bear the positive pull load decreases and the fatigue life of the joint decreases obviously. The heat affected zone of the spot welded joint of the thermoformed steel softens obviously. With the welding time prolongs , Heat affected zone softening degree has increased.