Weld Pool Shape Variations and Electrode Protection in Double Shielded TIG Welding

2010 ◽  
Vol 97-101 ◽  
pp. 3978-3981 ◽  
Author(s):  
Dong Jie Li ◽  
Shan Ping Lu ◽  
Dian Zhong Li ◽  
Yi Yi Li
Keyword(s):  
Weld Pool ◽  
Marangoni Convection ◽  
Welding Process ◽  
Tig Welding ◽  
Width Ratio ◽  
Mixed Gas ◽  
Pool Shape ◽  
Welding Method ◽  
Weld Depth ◽  
Weld Pool Shape

A new welding method named double shielded TIG welding has been investigated and is described in this paper. It is applicable to the TIG process and can improve the weld depth/width ratio and protect the electrode from oxidation during the welding process. A two pipeline structure is designed in the torch. Pure inert gas passes though the inner pipeline which keeps the arc stable and protects the tungsten electrode. A mixed gas containing an active gas passes through the outer pipeline. The active element which is decomposed from the active gas dissolves in the weld pool so as to change the Marangoni convection from an outward to an inward direction, and, as a result, the weld pool shape becomes deep and narrow. The double shielded TIG welding method increases the weld depth by about 2~3 times over the conventional TIG welding. The effects of the active gas (oxygen) in the outer pipeline on the weld pool shapes are discussed. Heavy oxide layer is considered to weaken the Marangoni convection and changes the weld pool shape.

Weld Pool Weld Width Prediction Based on Artificial Neural Network

2013 ◽  
Vol 462-463 ◽  
pp. 171-174
Author(s):  
Xiao Gang Liu ◽  
Le Ting Liu
Keyword(s):  
Neural Network ◽  
Weld Pool ◽  
Bp Neural Network ◽  
Arc Welding ◽  
Welding Process ◽  
Pool Shape ◽  
Weld Width ◽  
Network Method ◽  
Weld Pool Shape

In the COgas shielded arc welding, the weld pool forms is closely related to the quality of welding,but weld pool shape is affected by the welding process parameters. By using BP neural network to predict weld puddle weld width, the results show that the experimental data are very close, thus indicating that prediction of weld width through this network method is very effective.

Fluid Flow and Weld Pool Dynamics in Dual-Beam Laser Keyhole Welding

2003 ◽  
Author(s):  
J. Hu ◽  
H. L. Tsai
Keyword(s):  
Fluid Flow ◽  
Laser Welding ◽  
Weld Pool ◽  
Welding Process ◽  
Laser Beams ◽  
Pool Shape ◽  
Beam Laser ◽  
Dual Beam ◽  
Oval Shape ◽  
Weld Pool Shape

The use of dual or multiple laser beams is necessary for welding thick-section metals, especially for Nd:Yag lasers which are limited to relatively low power as compared to CO2 lasers. It was also reported that the use of dual laser beams for welding can increase keyhole stability leading to a better weld quality. So far, the development of dual-beam laser welding technologies has been in the experimental stage. The objective of this paper is to develop mathematical models and the associated numerical techniques to calculate the transient heat transfer and fluid flow in the weld pool and to study weld pool dynamics during the dual-beam laser welding process. The simulation was conducted for a three-dimensional stationary dual-beam laser welding. A very interesting change of the top-surface view of the weld pool was predicted. During the welding process, the top-view shape of the weld pool changes, starting from an oval-shape with the long-axis connecting the centers of the two laser beams, to a circle, and finally to an oval-shape with the short-axis connecting the centers of the two laser beams. Although a direct comparison with published experimental observation is impossible (due to the lack of detailed experimental data), the predicted weld pool shape is similar to that observed from experiments. The dynamical change of the weld pool shape can be well explained by the predicted fluid flow field.

Development of an advanced A-TIG (AA-TIG) welding method by control of Marangoni convection

2008 ◽  
Vol 495 (1-2) ◽  
pp. 296-303 ◽  
Author(s):  
Hidetoshi Fujii ◽  
Toyoyuki Sato ◽  
Shanping Lu ◽  
Kiyoshi Nogi
Keyword(s):  
Marangoni Convection ◽  
Tig Welding ◽  
Welding Method

Weld pool shape prediction in plasma augmented laser welded steel

2001 ◽  
Vol 6 (5) ◽  
pp. 305-314 ◽  
Author(s):  
J.M. Vitek ◽  
S.A. David ◽  
M.W. Richey ◽  
J. Biffin ◽  
N. Blundell ◽  
...  
Keyword(s):  
Weld Pool ◽  
Welded Steel ◽  
Pool Shape ◽  
Shape Prediction ◽  
Weld Pool Shape

The Effects of He–Ar-O2 Shielded Gas Addition on GTA Welding on Welded Shape of UNS S31803 Duplex Stainless Steel

2011 ◽  
Vol 214 ◽  
pp. 325-328
Author(s):  
Santirat Nansaarng ◽  
Suthiphong Sopha
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Marangoni Convection ◽  
Gta Welding ◽  
Width Ratio ◽  
Weld Penetration ◽  
Weld Shape ◽  
Convection Condition ◽  
Weld Depth ◽  
Oxygen Addition

The effects of oxygen in helium-argon base shielded GTAW on weld shape of weld penetration are systematically investigated by bead-on-pale welding on UNS S31803 duplex stainless steel. The results show that amount of oxygen addition to He-Ar mixed shielding can significantly change the weld shape from a wide narrow type to narrow deep one and the weld depth/width ratio can be doubled due to the change in Marangoni convection condition from an outward to an inward direction.

scholarly journals Effect of Torch Angle on Arc Properties and Weld Pool Shape in Stationary GTAW

2013 ◽  
Vol 139 (9) ◽  
pp. 1268-1277 ◽  
Author(s):  
S. Parvez ◽  
M. Abid ◽  
D. H. Nash ◽  
H. Fawad ◽  
A. Galloway
Keyword(s):  
Weld Pool ◽  
Pool Shape ◽  
Torch Angle ◽  
Weld Pool Shape

Molten Pool in Welding Processes: Phenomenological vs Fluid-Dynamic Numerical Simulation Approach

2017 ◽  
Vol 884 ◽  
pp. 26-40 ◽  
Author(s):  
Paolo Ferro
Keyword(s):  
Numerical Simulation ◽  
Residual Stresses ◽  
Fusion Zone ◽  
Weld Pool ◽  
Fluid Dynamic ◽  
Subsequent Development ◽  
Grain Structure ◽  
Pool Shape ◽  
Welding Processes ◽  
Weld Pool Shape

The metallurgical and mechanical properties of fusion welded joints are influenced, among others phenomena, by the weld pool dimension and shape. Weld pool shape is important in the development of grain structure and dendrite growth selection process as well as in the development of residual stresses. For these reasons, significant advances have been made in recent years to understand, in greater detail, the dynamics of the heat and fluid flow in the weld and the subsequent development of the pool shape. In numerical simulation of welding processes, there are two different approaches used to model the fusion zone. If the prediction of distortions and residual stresses is the primary objective of the simulation (computational weld mechanics simulation), the phenomenological approach is the most suitable method used to model the fusion zone. Otherwise, when the weld pool shape has to be predicted, the fluid-dynamic equations must be solved at the expense of a significant ‘computational load’ increase. In this work, after a brief description of weld pool characteristics, such two different approaches are described and compared.

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