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首页> 外文期刊>International Journal of Heat and Mass Transfer >Numerical investigation of weld pool behaviors and ripple formation for a moving GTA welding under pulsed currents
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Numerical investigation of weld pool behaviors and ripple formation for a moving GTA welding under pulsed currents

机译：脉冲电流作用下移动GTA焊接的熔池行为和波纹形成的数值研究

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摘要

The complex transport phenomena and their effects on the weld pool dynamics and surface rippling in moving gas tungsten arc welding (GTAW) under pulsed currents are studied by using a 3D transient numerical model. The distributions of the melt-flow velocity and temperature, and weld bead formation are simulated. The effects of welding conditions, including welding current waveform, pulse frequency and welding speed, on the weld penetration, formation and final appearance of ripples are discussed. It is found that surface ripples are formed under pulsed current due to the up-and-down weld pool motion, caused mainly by the periodically varied current and solidification rate of weld pool. The results show that for the cases with the same average current, the pulsed current leads to the deeper weld penetration than continuous current, and the higher peak current corresponds to the higher ripples and deeper penetration. The larger pulse frequency results in the more uniform thermal energy distributions on the workpiece and tends to decrease the solidification rate, leading to the more uniform penetration depths, the smaller pitch and height of the ripples. A slow travel speed is helpful to reduce pitch of the ripples but also at the risk of the reduced effective penetration. Finally, a CTAW experiment for the case of continuous current is conducted to validate the modeling predictions in terms of weld width, penetration depth and the formation of ripples.
机译：利用3D瞬态数值模型研究了移动气体钨极电弧焊（GTAW）中复杂的输运现象及其对焊池动力学和表面波纹的影响。模拟了熔体流动速度和温度的分布以及焊缝的形成。讨论了焊接条件（包括焊接电流波形，脉冲频率和焊接速度）对焊缝熔深，波纹形成和最终出现​​的影响。发现在脉冲电流的作用下，由于熔池上下运动而形成表面波纹，这主要是由周期性变化的电流和熔池的凝固速率引起的。结果表明，在平均电流相同的情况下，脉冲电流会比连续电流导致更深的焊接熔深，峰值电流越高，则波纹越大，熔深越深。较大的脉冲频率会导致工件上的热能分布更加均匀，并趋于降低凝固速率，从而导致更均匀的熔深，较小的螺距和波纹高度。缓慢的行进速度有助于减少波纹的间距，但也有降低有效穿透力的风险。最后，针对连续电流情况进行了CTAW实验，以根据焊缝宽度，熔深和波纹形成验证模型预测。

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  • 来源
    《International Journal of Heat and Mass Transfer》 |2015年第12期|990-1000|共11页
  • 作者

    J.W. Liu; Z.H. Rao; S.M. Liao; H.L. Tsai;

  • 作者单位

    School of Energy Science and Engineering, Central South University, 410083 Changsha, Hunan, China;

    School of Energy Science and Engineering, Central South University, 410083 Changsha, Hunan, China;

    School of Energy Science and Engineering, Central South University, 410083 Changsha, Hunan, China;

    Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    GTAW; Pulsed current; Weld pool; Ripple; Free surface;

    机译：GTAW;脉冲电流焊池波纹;自由表面;

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