锌合金线材冷压对焊与电阻对焊接头组织对比分析
Microstructure comparison of resistance butt welding and cold-pressure welding of zinc alloy wire
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摘要: 为提高锌合金线材生产中对焊接头的过模断裂率,采用金相显微镜、扫描电镜等手段观察分析了对焊接头拉伸和过模断口的组织形貌.结果表明,锌合金线材冷压焊接头拉伸断口是硬化材料的韧性断裂断口,在后续的拉拔生产前须进行退火处理,冷压焊接头经拉拔过模,原结合区变宽,结合区流线层间距加大,有助于缓解应力集中;锌合金线材电阻对焊接头结合区呈现明显的金属再结晶化晶粒长大组织,这种再结晶晶粒的产生有利于接头的内应力释放,使得接头具有较好的塑性变形能力,保证了电阻对焊接头具有很高的过模断裂率.Abstract: The fracture morphology of butt-welded joint with over mode was observed with metallographic microscope and scanning electron microscope (SEM) to enhance the overmoded rate of butt-welded joint of zinc alloy wire.The results show that the tension fracture of zinc alloy wire joint made by cold-pressure welding was ductile fracture of hardened material.The annealing should be performed ahead of the drawing process.After drawing the cold-pressure welded joint,the original bonding area widened and the separation of the streamline layers in bonded area became larger,and this was beneficial for releasing the stress concentration.The obvious grain growth with recrystallization occurred in resistance butt welded joint of zinc alloy wire.The generation of recrystallized grains was favorable for releasing the internal stress within the joint,which improved the plastic deformation capability of the joint and ensured the high overmoded rate of the resistance butt welded joint.