【摘要】 采用带匙孔搅拌摩擦点焊方法对1mm厚AZ31B镁合金板和1mm厚B140H1烘烤硬化高强钢板进行搭接焊接(镁板在上,钢板在下)。研究了焊接参数对接头表面成形和承载力的影响,以及最优参数下点焊接头的宏观形貌、微观组织、断口形貌和硬度。结果表明:随着搅拌头旋转速度增大、停留时间变长,接头剪切力呈先增大后减小的趋势,当转速为2 700r/min、停留时间为120s时,接头剪切力最大达到6.75kN;最大剪切力对应的接头成形较好,焊缝区晶粒呈细长和流动性明显的特征;搅拌区硬度最高达到180HV。更多还原

【Abstract】 Friction stir spot welding(FSSW)lap joint with key-hole between dissimilar materials of a 1 mm thick AZ31 Bmagnesium sheet and a 1 mm thick B140 H1 bake hardening high strength steel sheet(the magnesium sheet was placed on top and the steel sheet bottom)has been successfully made.The effects of welding parameters on the surface forming and load-carrying capacity of the joints have been studied,and the macro-morphology,micro-structure,fracture morphology and hardness of the spot welded joints under the optimal parameters are also studied.The results show that with the increase of rotating speed and residence time of stirring head,the shear stress of joint increases first and then decreases.When the rotational speed is 2 700 rad/min and the residence time is 120 s,the shear force of the joint reaches 6.75 kN.The maximum shear stress corresponds to better joint formation,and the grain size in the weld zone is slender and fluidity is obvious.The highest hardness of stirring zone is 180 HV.更多还原