摘要
针对7B04-T74铝合金,采用可变转速回填式搅拌摩擦点焊(variable rotation speed-refill friction stir spot welding,V-RFSSW)新方法开展了数值仿真及试验研究.结果表明,V-RFSSW温度场围绕搅拌头轴线呈圆形对称分布,焊点高温区域集中在搅拌套空腔内部.与扎入阶段转速相同的常规回填式搅拌摩擦点焊(refill friction stir spot welding,RFSSW)相比,V-RFSSW新方法既可在扎入阶段使材料充分塑化,以保证焊点成形,同时,通过降低回填阶段搅拌头转速降低焊接峰值温度及高温停留时间,抑制组分液化的发生,避免了共晶相的生成.V-RFSSW与常规RFSSW接头显微硬度均呈“W”形分布,且扎入阶段转速相同的情况下V-RFSSW接头搅拌区平均硬度更高.在拉剪载荷下两种接头均以“纽扣”形式发生断裂,其中V-RFSSW接头拉剪失效载荷为8 835 N,高于RFSSW接头的8 162 N.
For 7B04-T74 aluminum alloy, a new method of variable rotation speed refill friction stir spot welding(VRFSSW) was used. Numerical simulation and experiments were conducted. The results showed that the V-RFSSW temperature field was symmetrically distributed around the axis of the welding tool, and the high temperature area was concentrated in the cavity of the sleeve. Compared with the conventional refill friction stir spot welding(RFSSW) with the same rotation speed during the plunging stage, the new V-RFSSW method can fully plasticize the materials during the plunging stage to ensure the weld formation. At the same time, by reducing the rotation speed of the welding tool during the refilling stage, the welding peak temperature and high temperature dwelling time can be reduced, the occurrence of component liquefaction can be restrained and the formation of eutectic phase can be avoided. The microhardness distribution of the V-RFSSW joint and conventional RFSSW joint was "W" shape The average hardness of V-RFSSW joint was higher at the condition of the rotation speed iduring the plunging stage was the same. Under the tensile shear load, the two kinds of joints fractured in the form of "button", in which the tensile shear failure load of V-RFSSW joint was 8 835 N, which was higher than that of RFSSW joint(8 162 N).
作者
赵运强
赵宇佳
刘喆
林志成
董春林
邓军
ZHAO Yunqiang;ZHAO Yujia;LIU Zhe;LIN Zhicheng;DONG Chunlin;DENG Jun(China-Ukraine Institute of Welding,Guangdong Academy of Sciences,Guangdong Provincial Key Laboratory of Advanced Welding Technology,Guangzhou,510651,China;Guangdong Provincial Key Laboratory of Robotics and Digital Intelligent Manufacturing Technology,Guangzhou,510535,China)
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2022年第6期50-55,I0005,I0006,共8页
Transactions of The China Welding Institution
基金
国家自然科学基金资助项目(51905112)
广东省科协科技人计划项目(SKXRC202221)
广州市对外科技合作计划项目(201807010068)
东莞市重点领域研发项目(20201200300122)。
关键词
搅拌摩擦点焊
数值仿真
微观组织
力学性能
铝合金
friction stir spot welding
numerical simulation
microstructure
mechanical properties
aluminum alloy
