scholarly journals Prediction of the Weld Pool Stability by Material Flow Behavior of the Perforated Weld Pool

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 303
Author(s):  
Ruiqing Lang ◽  
Yongquan Han ◽  
Xueyu Bai ◽  
Haitao Hong
Keyword(s):  
Weld Pool ◽  
Material Flow ◽  
Flow Behavior ◽  
Maximum Velocity ◽  
Plasma Arc ◽  
Mechanical Coupling ◽  
Arc Pressure ◽  
Variable Polarity ◽  
Weld Pools ◽  
Variable Polarity Plasma Arc

This article presents the application of a computational fluid dynamics (CFD) finite volume method (FVM) model for a thermo-mechanical coupling simulation of the weld pool used in variable polarity plasma arc welding (VPPAW). Based on the mechanism of the additional pressure produced through self-magnetic arc compression and the jet generated from mechanical plasma arc compression, and considering the influence of arc height and keyhole secondary compression on arc pressure, a three-dimensional transient model of variable polarity plasma arc (VPPA) arc pressure was established. The material flow behaviors of the perforated weld pools were studied. The results show that three kinds of flow behavior existed in the perforation weld pools and it is feasible to predict the weld pool stability by the material flow behaviors of the perforated weld pools. The weld pools can exist stably if the material flow in the bottom of the perforated weld pools can form confluences with moderate flow velocities of 0.45 m/s, 0.55 m/s and 0.60 m/s. The weld pools were cut when the material flowed downward and outward with the maximum velocity of 0.70 m/s, 0.80 m/s. When the maximum material flow velocity was 0.40 m/s, the weld pool collapsed downward under the action of larger gravity. The thermo-mechanical coupling model was verified by the comparison of the simulation and experimental results.

scholarly journals Effect of Arc Pressure on the Digging Process in Variable Polarity Plasma Arc Welding of A5052P Aluminum Alloy

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1071 ◽  
Author(s):  
Bin Xu ◽  
Shinichi Tashiro ◽  
Fan Jiang ◽  
Shujun Chen ◽  
Manabu Tanaka
Keyword(s):  
Weld Pool ◽  
High Speed ◽  
Imaging System ◽  
Physical Phenomenon ◽  
Plasma Arc ◽  
Arc Pressure ◽  
Variable Polarity ◽  
Welding Stability ◽  
Energy And Momentum ◽  
Variable Polarity Plasma Arc

The keyhole digging process associated with variable polarity plasma arc (VPPA) welding remains unclear, resulting in poor control of welding stability. The VPPA pressure directly determines the dynamics of the keyhole and weld pool in the digging process. Here, through a high speed camera, high frequency pulsed diode laser light source and X-ray transmission imaging system, we reveal the potential physical phenomenon of a keyhole weld pool. The keyhole depth changes periodically corresponding to the polarity conversion period if the current is same in the electrode negative (EN) phase and electrode positive (EP) phase. There exist three distinct regimes of keyhole and weld pool behavior in the whole digging process, due to the arc pressure attenuation and energy accumulation effect. The pressure in the EP phase is smaller than that of the EN phase, causing the fluctuation of the weld pool free surface. Based on the influence mechanism of energy and momentum transaction, the arc pressure output is balanced by separately adjusting the current in each polarity. Finally, the keyhole fluctuation during the digging process is successfully reduced and welding stability is well controlled.

Experimental Analysis of Welding Parameters on Variable Polarity Plasma Arc Pressure

2013 ◽  
Vol 651 ◽  
pp. 355-360 ◽  
Author(s):  
Yi Jiang ◽  
Ming Liu ◽  
Yao Hui Lu ◽  
Bin Shi Xu
Keyword(s):  
Arc Welding ◽  
Gas Flow ◽  
Welding Current ◽  
Welding Parameters ◽  
Plasma Arc Welding ◽  
Plasma Arc ◽  
Arc Pressure ◽  
Variable Polarity ◽  
Reversed Polarity ◽  
Variable Polarity Plasma Arc

Variable polarity plasma arc welding has been widely used to manufacture industries. The effects of welding current and plasma gas flow as the most important parameters on variable polarity plasma arc pressure were discussed experimentally. To welding current, two experimental were designed to discuss the effects of straight polarity current and reversed polarity current on arc pressure respectively. It could be concluded that arc pressure is quadratic with welding current. To plasma gas flow, both experimental and numerical analysis are used to discuss the mechanisms of plasma gas flow to arc pressure, and it could be conclude that arc pressure is quadratic with plasma gas flow rather than linear.

Physical mechanism of material flow in variable polarity plasma arc keyhole welding revealed by in situ x-ray imaging

2021 ◽  
Vol 33 (1) ◽  
pp. 017121
Author(s):  
Bin Xu ◽  
Shujun Chen ◽  
Shinichi Tashiro ◽  
Fan Jiang ◽  
Manabu Tanaka
Keyword(s):  
Material Flow ◽  
Physical Mechanism ◽  
Plasma Arc ◽  
X Ray ◽  
Keyhole Welding ◽  
X Ray Imaging ◽  
Variable Polarity ◽  
Variable Polarity Plasma Arc

Material flow in variable polarity plasma arc keyhole welding of aluminum alloy

2018 ◽  
Vol 36 ◽  
pp. 480-486 ◽  
Author(s):  
Zhaoyang Yan ◽  
Shujun Chen ◽  
Fan Jiang ◽  
Ning Huang ◽  
Suolai Zhang
Keyword(s):  
Aluminum Alloy ◽  
Material Flow ◽  
Plasma Arc ◽  
Keyhole Welding ◽  
Variable Polarity ◽  
Variable Polarity Plasma Arc

The influence mechanism of variable polarity plasma arc pressure on flat keyhole welding stability

2019 ◽  
Vol 37 ◽  
pp. 519-528 ◽  
Author(s):  
Bin Xu ◽  
Shujun Chen ◽  
Fan Jiang ◽  
Huy Le Phan ◽  
Shinichi Tashiro ◽  
...  
Keyword(s):  
Plasma Arc ◽  
Keyhole Welding ◽  
Influence Mechanism ◽  
Arc Pressure ◽  
Variable Polarity ◽  
Welding Stability ◽  
Variable Polarity Plasma Arc

The effect of electrode energy balance on variable polarity plasma arc pressure

2019 ◽  
Vol 145 ◽  
pp. 118715 ◽  
Author(s):  
Bin Xu ◽  
Shinichi Tashiro ◽  
Fan Jiang ◽  
Manabu Tanaka ◽  
Shujun Chen
Keyword(s):  
Energy Balance ◽  
Plasma Arc ◽  
Arc Pressure ◽  
Variable Polarity ◽  
Variable Polarity Plasma Arc

scholarly journals Numerical Analysis of Keyhole and Weld Pool Behaviors in Ultrasonic-Assisted Plasma Arc Welding Process

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 703
Author(s):  
Junnan Qiao ◽  
Chuansong Wu ◽  
Yongfeng Li
Keyword(s):  
Shear Stress ◽  
Weld Pool ◽  
Arc Welding ◽  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Plasma Arc Welding ◽  
Plasma Arc ◽  
Arc Pressure ◽  
Ultrasonic Assisted

The acoustic radiation force driving the plasma jet and the ultrasound reflection at the plasma arc-weld pool interface are considered to modify the formulas of gas shear stress and plasma arc pressure on the anode surface in ultrasonic-assisted plasma arc welding (U-PAW). A transient model taking into account the dynamic changes of heat flux, gas shear stress, and arc pressure on the keyhole wall is developed. The keyhole and weld pool behaviors are numerically simulated to predict the heat transfer and fluid flow in the weld pool and dynamic keyhole evolution process. The model is experimentally validated. The simulation results show that the acoustic radiation force increases the plasma arc velocity, and then increases both the plasma arc pressure and the gas shear stress on the keyhole wall, so that the keyholing capability is enhanced in U-PAW.

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