Three–dimensional modeling of weld pool dynamics and surface rippling during pulsed GTAW
The complex transport phenomena and their effects on weld pool dynamics and the formation of surface ripples in moving gas tungsten arc welding (GTAW) under the pulsed current are studied by using a 3D transient numerical model. The transient distributions of the melt flow velocity and temperature in the weld pool, weld pool dynamics, and weld bead formation are simulated. The effects of welding conditions, including the welding current waveform, pulsed current frequency and welding speed, on the formation and final appearance of ripples are discussed. It is found that the surface ripples are formed under the pulsed current by the interplay between the up–and–down weld pool dynamics, caused mainly by the periodically varied current, and solidification rate of weld pool. The predicted ripple shape and average pitch are close to the published experimental results. Under the continuous current, surface rippling is not observed due to the continuous weld pool dynamics and solidification. This study shows that the current has significant effects on the weld pool dynamics and weld bead shape in GTAW. As the welding current increases, the weld pool size and the weld penetration depth increase due to the more intensive arc heating in the same duration. The larger pulsed current frequency tends to decrease the solidification rate and thus the pitch and height of the ripples are reduced. A slow welding speed results in the small pitch of the ripples but may reduce the effective penetration.
GTAW pulsed current weld pool ripple numerical simulation
Zhenghua Rao Ruchao Gao Jiangwei Liu Shengming Liao Hai–Lung Tsai
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, R
国际会议
济南
英文
1-14
2012-08-24（万方平台首次上网日期，不代表论文的发表时间）