钛合金胶接点焊与电阻点焊接头性能对比分析

分别对1.5 mm厚的钛合金板进行胶接点焊和电阻点焊连接,获得了不同焊接电流下的胶接点焊和电阻点焊接头，从熔核的C扫描图像、接头的失效载荷和断口形貌等方面，对比分析了胶接点焊和电阻点焊的接头强度及失效样貌. 结果表明,通过观察A扫描信号的变化与C扫描图像的特征，能够很好的划分接头的热影响区、熔合区、熔核区以及检测出接头的熔核直径和焊接缺陷. 随着焊接电流(7.0～10.0 kA)的逐渐增大，接头熔核直径及失效载荷呈递增趋势；当焊接条件相同时，胶接点焊接头的熔核直径普遍大于电阻点焊接头，但接头的强度相当. 当电流在7.0～8.5 kA时，接头强度不足，熔核区的断口处出现大小不等的韧窝，呈现出韧性断裂特征；当电流为10.0 kA时，接头强度较高，主要呈现出韧性断裂与准解理断裂特征.

Comparison of joint performance between spot weld bonding and resistance spot welding of titanium alloy

The technology of spot weld bonding and resistance spot welding was applied to 1.5 mm titanium alloy sheet. The spot weld bonding and resistance spot welding joints were acquired under different welding current. The joint strength and failure feature between spot weld bonding and resistance spot welding (RSW) were compared by C-scan images of nuggets, the failure load of joints and fracture morphology. Results show that the change A-scan signals and the characteristics of C-scan images can divide heat affected zone, melting area, nugget zone. It can detect nugget diameters and weld defects of joints, too. The nugget diameters of joints increase with the increase of welding current. When the welding process parameters are the same, the nugget diameters of spot weld bonding is generally larger than the nugget diameters of resistance spot welding. But their strength is similar. When the welding current is changed from 7.0 kA to 8.5 kA, there are many different size dimples of the fracture surface, which present ductile fracture. When the welding current is 10.0 kA, the joints are mainly ductile fracture and quasi-cleavage fracture.