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采用光纤激光器对6016车用铝合金与DC56D镀锌钢搭接接头进行了激光焊接试验研究。研究了焊接速度对铝/钢搭接接头熔深、界面金属间化合物和强度的影响,以及单焊缝与双焊缝两种焊缝布置形式的接头强度差异。采用扫描电子显微镜(SEM)和能谱仪(EDS)对焊接接头显微结构、金属间化合物成分以及拉伸断裂试样的断口进行了观察测试。结果表明,选择适当的焊接速度,控制熔深在合适范围内时,可获得较高强度的焊接接头。接头界面处生成的金属间化合物主要有Fe2Al5,FeAl2和FeAl33种。采用双焊缝布置形式可有效提高焊接接头强度,接头最大拉剪强度可达155 N/mm,约为铝合金母材抗拉强度的84%,相对单焊缝布置接头提高了26%;拉伸试样断裂在铝合金热影响区处,断裂属于韧窝断裂。
A laser welding experiment on 6016 automotive aluminum alloy and DC56D galvanized steel lap joint was carried out. The effect of welding speed on the penetration depth, interface intermetallic compounds and strength of aluminum / steel lap joints and the strength of joints between two kinds of single and double welds were studied. The microstructure of the welded joint, intermetallic composition and the fracture of the tensile fracture specimen were observed by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The results show that when the proper welding speed is selected and the welding depth is controlled within the proper range, a higher strength welded joint can be obtained. Interfacial interface generated intermetallic compounds mainly Fe2Al5, FeAl2 and FeAl33 species. The double weld arrangement can effectively improve the strength of the welded joint. The maximum tensile shear strength of the joint can reach 155 N / mm, which is about 84% of the tensile strength of the aluminum alloy base. Compared with the single welded joint, the joint is increased by 26% Tensile specimen fracture in the heat affected zone of the aluminum alloy, the fracture belongs to dimple fracture.