镀锌钢-1420铝锂合金电阻点焊及压印接头连接强度对比

Strength Comparison of Resistance Spot Welding and Clinching joints of Galvanized Steel and 1420 Aluminum Lithium Alloy

对镀锌钢-1420铝锂合金电阻点焊接头及压印接头进行强度对比,利用超声扫描显微镜,分析镀锌钢-1420电阻点焊接头的C扫描图像,得到电阻点焊焊核内部各个区域的特征;采用直接观测法观察镀锌钢-1420压印接头的成形质量;通过MTS材料试验机进行拉伸-剪切试验,得到电阻点焊接头和压印接头的静失效载荷、失效形式及能量吸收值。结果表明：电阻点焊和压印连接都能很好地对镀锌钢-1420进行连接;在镀锌钢-1420异种板材的拉伸-剪切试验中,电阻点焊接头的静拉伸载荷（4593.8 N）高于压印接头的静拉伸载荷（3119.3 N）;电阻点焊接头的失效模式为部分界面撕裂,压印接头的失效模式为上板拉脱失效并伴随部分上板颈部断裂;镀锌钢-1420压印接头的能量吸收值（4.757 J）要大于电阻点焊接头的能量吸收值（3.861 J）,压印接头有良好的能量吸收能力,缓冲吸震性强。

The strength of resistance spot welding and clinching joints of galvanized steel-1420 Al-Li alloys sheets was compared. The C scanning image of the resistance spot welding joint was analyzed by using the ultrasonic scanning microscope, and the characteristics of each area inside the weld core were obtained. The forming quality of clinching joint of galvanized steel-1420 sheets was observed by direct observation. The static failure load, failure mode and energy absorption of the resistance spot welding and clinching joints were analyzed by tensile-shear test through MTS material test machine. The results show that both resistance spot welding and clinching can connect galvanized steel and 1420 alloy sheets. In the tensile-shear test of galvanized steel-1420 dissimilar sheets, the static tensile load（4593.8 N） of the resistance spot welding joint is higher than that（3119.3 N） of the clinching joint.The failure mode of resistance spot welding joint is partial interface tear, and the failure mode of the clinching joint is pulling out of upper plate with neck fracture of the upper plate. The energy absorption value of galvanized steel-1420 clinching joint（4.757 J） is larger than that of resistance spot welding joint（3.861 J）,and the clinching joint has good energy absorption ability, and the cushioning shock absorption of clinching joint is strongest.