基于定量分析方法的焊接位置对激光焊接熔池流动行为影响规律的研究

发布时间：2018-04-21 03:10

本文选题：激光焊接 + 焊接位置　；参考：《应用激光》2017年01期

【摘要】：激光熔池流动模式和熔池流动特征决定了焊缝成形和焊接缺陷的分布,因此研究不同焊接位置对激光焊接流动行为的影响对优化焊接位置和焊接参数具有重要意义。采用1.5kW板条型CO_2气体激光进行了平焊和立焊向上、立焊向下等不同焊接位置下的焊接试验,并采用高速摄像对其熔池小孔特征进行了监测,再采用粒子图像测速(PIV)方法对熔池流动特征进行了定量表征和分析。明确了激光焊接时的熔池流动模式,在熔池区域存在着两个大的涡流区域,分别在熔池周围和在熔池的尾部。与立向上焊相比,激光立向下焊的熔池形状呈扁圆形,宽度增加而长度减少,小孔的面积增加,其熔池流动的脉冲特征减弱,熔池流动的稳定性增加。这与立向下焊时熔池上方液态金属受重力影响向下流动,与下方液态金属受蒸汽反冲压等驱动向上流动,两者相遇产生的强烈搅拌作用有关。这为理解不同焊接位置不同的焊缝成形和气孔率差异提供了依据。
[Abstract]:The distribution of weld forming and welding defects is determined by laser pool flow mode and weld pool flow characteristics. Therefore, it is important to study the influence of different welding positions on laser welding flow behavior for optimizing welding position and welding parameters. The welding experiments were carried out in different welding positions, such as horizontal welding, vertical welding, vertical welding and vertical welding with 1.5kW slab CO_2 gas laser, and the characteristics of weld pool holes were monitored by high speed video. The particle image velocimetry (PIV) method was used to quantitatively characterize and analyze the flow characteristics of the molten pool. The flow mode of the molten pool during laser welding is clarified. There are two large eddy current regions in the weld pool region, one around the pool and the other at the end of the pool. Compared with vertical upward welding, the weld pool of laser vertical downward welding is oblate, the width increases, the length decreases, the area of the holes increases, the pulse characteristic of the molten pool flow weakens, and the stability of the molten pool flow increases. This is related to the downward flow of the liquid metal above the molten pool under the influence of gravity and the upward flow of the liquid metal under the driving force of steam back stamping during vertical downward welding. This provides a basis for understanding the difference of weld formation and porosity in different welding positions.
【作者单位】：中国工程物理研究院机械制造工艺研究所;
【基金】：国家自然科学基金资助项目(项目编号:51005219) 中国工程物理研究院科学技术发展基金重点资助项目(项目编号:2013A0203008)
【分类号】：TG456.7

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