采用辅助能量的搅拌摩擦焊新工艺

New processes of secondary energy assisted friction stir welding

常规搅拌摩擦焊一般需要很大的轴向压力和搅拌头转矩来产生足够的摩擦热和塑性功来软化材料形成焊缝。这会导致搅拌头磨损,并限制焊接速度的提高,尤其是在焊接高强高硬材料时,这种问题变得更加突出。为了解决这些问题,研究人员通常采用辅助能源(激光、电弧热、电阻热、感应热等)来协助软化待焊材料,从而降低轴向压力和搅拌头转矩,并提高焊接速度。然而,对于作为固相连接的搅拌摩擦焊,这种直接加热的方式往往具有一些固有的不足之处。作为一类机械能,超声振动能够在无显著加热的条件下降低金属材料的变形抗力。因此,利用超声振动作为辅助能源,构成超声强化的搅拌摩擦焊新工艺,可改善焊接质量、降低焊接载荷、提高焊接速度,具有很大的发展潜力。文中对这些采用外加辅助能量的搅拌摩擦焊新工艺技术进行了评述,并对该领域下一步的研发方向进行了展望。

In conventional friction stir welding(FSW),high axial force and tool torque are necessary to guarantee sufficient heat generation,which may cause the tool wear and limit the welding speed,especially in welding high strength and high hardness materials.To solve these problems,some researchers used secondary heat sources(laser,electric arc,electric resistance and induction) to assist softening of the material to lower the required axial force and tool torque,and increase the welding speed.However,the extra heating may lead to some inherent disadvantages because FSW itself is a solid — state welding process.As a kind of mechanical energy,ultrasonic vibration can remarkably decrease the deformation resistance of the metallic materials without significant heating.Therefore,ultrasonic vibration is of application potential for lowering the welding load and improving the welding speed.Ultrasonic vibration enhanced friction stir welding(UVeFSW) can improve the microstructure and mechanical properties of joint,so that it has great application potential.The development of such external auxiliary energy assisted FSW processes was reviewed,and an outlook of the main development tendency in this field was given.