摘要: |
本文选用1mm厚2A12-T4铝合金薄板进行搅拌摩擦搭接焊实验,通过改变焊接速度,研究其对焊接界面hook沟成形特征及接头力学性能的影响。结果表明,hook沟成形特征受焊接热输入影响较大,当采用95mm/min低焊接速度焊接时,由于焊接热输入大,塑性金属沿焊缝厚度方向上发生剧烈的环形迁移运动,促使hook尾部向上弯曲并堆积大量金属氧化物,有效搭接厚度较小;增加焊接速度至118mm/min时,焊接热输入降低,焊核区塑性金属挤压界面冷金属向上迁移的能力下降,导致hook沟尾部开始向下弯曲;继续提高焊接速度至235mm/min时,hook尾部受到塑性金属向下迁移的力大于向上迁移的力,迫使其向下弯曲,但在尾部产生了机械互锁效应,且焊缝有效搭接厚度明显增大,所获的接头拉剪力最大,高达3.790kN,其平均抗拉线强度为400N/mm,接头呈现明显的韧性断裂;继续增大焊接速度,则不利于提高接头成形质量。 |
关键词: 铝合金薄板;搅拌摩擦搭接焊;hook沟;成形特征;力学性能 |
基金项目:国家自然科学基金(52****45);江西省主要学科学术和技术带头人培育计划青年人才项目(2021****23028);江西省杰出青年基金项目(2022****214012);江西省研究生创新专项资金项目(YC2***-***9)。 |
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Formation Characteristic of hook at the Interface and Its Influence on Mechanical Properties of Friction Stir Welding Aluminum Alloy Sheet Joints |
Wang Jinkai1, Mao Yuqing1, Dai Hao2, Peng Qianqun1, Li Zhiyong2, Liu Zeyu2, Ke Liming1
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1. National Defence Key Discipline Laboratory of Light Alloy Processing Science and Technology,
Nanchang Hangkong University, Nanchang 330063;2. Jiangxi Changhe Aviation Industry Co., Ltd., Jingdezhen 333002
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Abstract: |
In this paper, 2A12-T4 aluminum alloy sheet with a thickness of 1mm were selected for friction stir lap welding (FSLW), and influence of welding speed on hook formation characteristic and mechanical properties of FSLW joints was studied. The results show that, the formation characteristic of the hook is greatly affected by welding heat input. When a low welding speed of 95mm/min is used during FSLW process, as the welding heat input is large, weld plastic metal generates a violent circular migration along the thickness direction, and which causes the end of hook bending upward and a large amount of metal oxides accumulate, resulting in a small effective sheet thickness. When the welding speed is increased to 118mm/min, the welding heat input decreases, and the ability of cold metal to migrate upward decreases at the welding interface, resulting in the hook end beginning to bend downward. Increasing continuously welding speed to 235mm/min, the driving force of migration downward of the hook end is greater than that of the migration upward, causing the hook end bending downward. Moreover, a phenomenon of mechanical interlocking forms at the end, and the effective sheet thickness of the weld significantly increases, which can result in a maximum tensile shearing force of 3.790kN. The average tensile shearing strength is 400N/mm. The fracture mode of the joints presents obvious ductile fracture.It is not conducive to improving the forming quality of the joints with further increasing the welding speed. |
Key words: aluminum alloy sheet;friction stir lap welding;hook;formation characteristic;mechanical properties |