摘要:
摩擦点焊是在搅拌摩擦焊基础上开发的一种新型固态连接技术。针对2 mm厚的LY12铝合金,研究了摩擦点焊过程中的焊接工艺参数对焊点成形及力学性能的影响。结果表明,当焊接时间一定,搅拌头旋转速度较高时,焊点的表面成形较好;随着搅拌头旋转速度的降低,焊点的表面成形逐渐变差。焊点的抗剪载荷随搅拌头旋转速度增加呈现出先增大后减小的趋势,当搅拌头旋转速度为950 r/min、焊接时间为8 s时,焊点的抗剪载荷达到最大值,为9.33 kN/点。焊点横截面的显微硬度测试结果表明,显微硬度沿匙孔中心呈高-低-较高-低-高的"W"形分布,最小值出现在热影响区,塑性区的显微硬度较高,但略小于母材。
Abstract:
Friction stir spot welding (FSSW) is a relatively new solid state joining method, which is a variant of friction stir welding.The effect of the welding parameters on the shaping and mechanical properties of friction stir spot welded joint of 2 mm LY12 Al alloy was investigated.The results show that, when the welding time is fixed, welding spot appearamce is better with the increasing of the tool rotation speed, and it becomes worse with the decrease of the tool rotation speed and the welding time.The tensile shear strength of the spot increases firstly, and then reduces with the increasing of tool rotation speed.When the tool rotation speed is 950 r/min and welding time is 12 s, the maximum strength is up to 9.33 kN/spot.The microhardness show that the distribution of microhardness is high-low-sight higher-low-high along the centre of the keyhole, and the minimum value is in the heat affected zone, and the microhardness of plasticity zone was slightly lower than that of base metal.
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