| 6061-T6铝合金DP-MIG焊轧复合成形接头组织与力学性能 |
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| 引用本文： | 宋刚,董孝南,程继文,王泽力,刘黎明.6061-T6铝合金DP-MIG焊轧复合成形接头组织与力学性能[J].焊接学报,2023,44(4):1-6+29+129. |
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| 作者姓名： | 宋刚 董孝南 程继文 王泽力 刘黎明 |
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| 作者单位： | 大连理工大学, 辽宁省先进连接技术重点实验室, 大连, 116024 |
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| 基金项目： | 国家自然科学基金资助项目(U1960111)；中央高校基本科研业务费专项资金资助项目(DUT21LAB133). |
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| 摘 要： | 为解决6061-T6铝合金焊后热影响区软化导致力学性能下降的问题，基于焊接接头余高大变形强化过时效软化区的思想，采用双轧辊系统对6061-T6薄板铝合金直流双脉冲熔化极气体保护焊(DC double pulse metal inert gas welding,DP-MIG焊)接头进行同步双面轧制，并分析了焊轧复合成形接头组织与力学性能.结果表明，焊缝晶粒受到竖直方向的轧制力发生大塑性变形，内部气孔消失，焊缝区域变宽，邻近焊缝的热影响区受到来自焊缝的挤压力发生协同宏观变形，远离焊缝的过时效软化区组织受到来自焊缝处的压应力，从沿垂直焊缝方向产生部分协同形变强化；接头的硬度明显提升，过时效软化区的硬度由60～70 HV提升至80～90 HV，过时效软化区的拉伸性能也有所提升，当焊接速度为800 mm/min时，抗拉强度最佳可达到母材的83.6%，相较于焊接接头提升19.4%，进而实现了对过时效软化区的强化效果.
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| 关 键 词： | 铝合金 热影响区软化 直流双脉冲熔化极气体保护焊 焊轧复合成形 |
| 收稿时间： | 2022-05-11 |
Microstructure and mechanical properties of DP-MIG welding-rolling composite forming joints of 6061-T6 aluminum alloy |
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| Affiliation: | Key Laboratory of Advanced Connectivity Technology of Liaoning Province, Dalian University of Technology, Dalian, 116024, China |
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| Abstract: | To solve the problem of degrading of mechanical properties of as welded 6061-T6 aluminum alloy joint caused by softening of the heat-affected zone, this study applied a double-roller system to perform simultaneous double-sided rolling on 6061-T6 thin aluminum alloy DC double pulse metal inert gas (DP-MIG) welded joints, based on the idea of utilizing welding residual height and large deformation to strengthen the over-aging softened zone. The microstructure and mechanical properties of the welding-rolling composite forming joints were analyzed. The results are as follows: the weld grain is subjected to large plastic deformation by the vertical rolling force; The internal pores disappear, thus the weld area widens. The heat-affected zone adjacent to the weld is subjected to co-macro deformation by the extrusion force from the weld, and the over-aging softened zone far from the weld is subjected to compressive stress from the weld, resulting in partial co-deformation strengthening along the vertical weld direction. The overall hardness of the joints is significantly improved with the hardness of the over-aging softened zone, which increased from 60 ? 70 HV to 80 ? 90 HV. The tensile properties of the over-aging softened zone are improved. When the welding speed is 800 mm/min, the best tensile strength can reach 83.6% of that of the base metal, 19.4% higher than that of the welded joint, which is a notable improvement to the over-aging softened zone. |
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