流动摩擦点焊界面质量控制研究

Study on Controlling of Interface of Friction Flow Spot Welding

对1mm厚6061-T6铝合金进行流动摩擦点焊试验,通过测试各种工艺条件下的焊接接头剪切性能,结合金相组织观察及断裂特征分析,研究了不同工艺参数对焊接接头焊核区、热机影响区、热影响区微观组织和剪切性能的影响。结果表明:在本次试验研究范围内,随着搅拌头焊接转速和焊接时间的增加,焊接接头的剪切性能逐渐提高;当焊接转速与焊接时间确定时,焊接接头的剪切性能随下压力的逐步增加呈现先增大后减小的趋势。当下压力F≤2300N时,"Hook"缺陷未上翘至上板顶部,焊点断裂模式为"剪切"断裂;当下压力F>2300N时,"Hook"缺陷上翘至上板顶部,焊点断裂模式为"插入"断裂。当下压力F=2300N,搅拌头旋转速度为2000r/min,焊接时间为10s时,1mm厚6061-T6铝合金流动摩擦点焊接头剪切性能和成型质量较好。

The friction flow spot welding experiment has been performed on 1 mm thick aluminum alloy 6061-T6. The process, microstructure and properties of welded joints were analyzed. The results show that the welded joints can be divided into four regions namely weld nugget zone, thermo-mechanical affected zone, heat affected zone and base material zone. The weld nugget zone has the tiniest grains. Down force, welding rotational speed and welding time have influences on the properties of the welded joints. In this paper, the author selects down force as the parameter for controlling the plunge depth of the tool. When down force ≤ 2300 N, the hooking defeat hasn＇t inserted into the top surface of the upper sheet, the fracture mode acts as the ＂shear fracture＂. When down force 〉2300 N, the fracture mode acts as the ＂plug fracture＂. The study shows that when choosing down force 2300 N, welding rotational speed 2000 r/min, welding time 10 s as the welding parameter, good weld joints of 1 mm thick aluminum alloy 6061-T6 can be got.