纯铝1060/镀锌钢电阻点钎焊工艺及接头性能

Study on welding process and mechanical properties of resistance spot brazed pure aluminum 1060 to galvanized steel

关键词:  纯铝  镀锌钢  电阻点钎焊  微观组织  力学性能

Key words:  pure aluminum  galvanized steel  resistance spot brazing  microstructure  mechanical properties

摘要:

采用电阻点钎焊进行了纯铝1060与SGCC热镀锌钢板的搭接试验，研究了接头界面组织，并测试了接头力学性能. 结果表明，试验所用铝硅（Al-Si）合金钎料润湿良好，焊后接头焊缝界面处产生了具有双层结构且厚度不均的金属间化合物，厚度小于10 μm；焊接电流为7.8 kA时，接头抗拉剪载荷达到峰值，约为4.72 kN，在相同工艺参数下，电阻点钎焊接头的抗拉剪载荷明显高于点焊接头；接头断裂大都发生在铝板侧，且主要在热影响区处而不在焊点处，说明点钎焊接头质量良好，但由于焊缝铝侧界面局部存在“未钎合”缺陷，焊缝界面会产生拉应力且在金属间化合物的应力作用下易产生裂纹.

Abstract:

Resistance spot brazing of pure aluminum 1060 to SGCC hot-dip galvanized steel was investigated. The microstructure of the intermetallic compound (IMC) in the interfacial layer was analyzed, and the mechanical properties of the joint was tested. The results showed that the aluminum-silicon brazing filler metal had a well wettability, and the intermetallic compound with double-layer structure and uneven thickness less than 10 μm generated at the interface of the welded joint. When the welding current was 7.8 kA, the maximum tensile shear load of the joint was 4.72 kN, which was significantly higher than that of the resistance spot welding joint under the same process parameters. The fracture of the joint mostly occured on the side of aluminum plate, and it was mainly in the heat affected zone (HAZ) rather than the welding spot, indicating that the resistance point brazing joint was of good quality. However, the local incomplete brazing was found in the weld interface at the aluminum side, where the tensile stress was generated, and the weld interface tended to crack under the stress of the intermetallic compound.