Influences of Sign of Surface Tension Coefficient on Turbulent Weld Pool Convection in a Gas Tungsten Arc Welding (GTAW) Process: A Comparative Study

2005 ◽  
Vol 127 (8) ◽  
pp. 848-862 ◽  
Author(s):  
Nilanjan Chakraborty ◽  
Suman Chakraborty
Keyword(s):  
Surface Tension ◽  
Weld Pool ◽  
Arc Welding ◽  
Surface Tension Coefficient ◽  
Scaling Analysis ◽  
Gas Tungsten Arc ◽  
Gtaw Process ◽  
Order Of Magnitude ◽  
Negative Surface ◽  
Surface Tension Coefficients

The effects of positive and negative surface tension coefficients (∂σsur∕∂T) on both laminar and turbulent weld pool convection are numerically studied for a typical gas tungsten arc welding (GTAW) process. Three-dimensional turbulent weld pool convection in a pool is simulated using a suitably modified high Reynolds number k‐ε model in order to account for the morphology of an evolving solid-liquid interface. Key effects of the sign of surface tension coefficient (∂σsur∕∂T) on the turbulent transport in a GTAW process are highlighted by comparing the turbulent simulation results with the corresponding ones from a laminar model, keeping all other process parameters unaltered. A scaling analysis is also performed in order to obtain order-of-magnitude estimates of weld pool penetration for both positive and negative surface tension coefficients. The scaling analysis predictions are in good agreement with the numerical results, in an order-of-magnitude sense.

Advanced Scaling Techniques for the Modeling of Materials Processing

2009 ◽  
Author(s):  
Karem Tello ◽  
Ustun Duman ◽  
Patricio Mendez
Keyword(s):  
Weld Pool ◽  
Arc Welding ◽  
Maximum Temperature ◽  
Scaling Analysis ◽  
Weld Penetration ◽  
Friction Stir ◽  
Gas Tungsten Arc ◽  
Pool Surface ◽  
Scaling Models ◽  
Welding Processes

The present work presents how scaling analysis can be applied into multiphysics and multicoupled problems related to welding processes. The formation of the weld pool surface depression in high current and velocity Gas Tungsten Arc Welding (GTAW) is dominated by the gas shear acting on the weld pool. Considering this dominant force the weld penetration was estimated and compared to experimental results. Plastic deformation and heat flow are coupled phenomena in Friction Stir Welding (FSW), the maximum temperature was estimated using scaling analysis and compared with experimental and numerical results reported in the literature. Although the simplicity of the scaling models, they are capable of capturing correct trends and order of magnitudes of the unknown estimations in a problem. Moreover, they are capable of determining the dominant forces that act on the process studied.

scholarly journals Arc Characteristics and Weld Bead Microstructure of Ti-6Al-4V Titanium Alloy in Ultra-high Frequency Pulse Gas Tungsten Arc Welding (UHFP-GTAW) Process

2020 ◽  
Vol 26 (4) ◽  
pp. 426-431
Author(s):  
Wei LI ◽  
Gaochong LV ◽  
Qiang WANG ◽  
Songtao HUANG
Keyword(s):  
Titanium Alloy ◽  
Fusion Zone ◽  
Arc Welding ◽  
Gas Tungsten Arc Welding ◽  
Weld Bead ◽  
Gas Tungsten Arc ◽  
Arc Characteristics ◽  
Arc Pressure ◽  
Gtaw Process ◽  
Gas Tungsten

To resolve the problem of grain coarsening occurring in the fusion zone and the heat-affected zone during conventional gas tungsten arc welding(C-GTAW) welded titanium alloy, which severely restricts the improvement of weld mechanical properties, welding experiments on Ti-6Al-4V titanium alloy by adopting ultra-high frequency pulse gas tungsten arc welding (UHFP-GTAW) technique were carried out to study arc characteristics and weld bead microstructure. Combined with image processing technique, arc shapes during welding process were observed by high-speed camera. Meanwhile the average arc pressure under various welding parameters were obtained by adopting pressure measuring equipment with high-precision. In addition, the metallographic samples of the weld cross section were prepared for observing weld bead geometry and microstructure of the fusion zone. The experimental results show that, compared with C-GTAW, UHFP-GTAW process provides larger arc energy density and higher proportion of arc core region to the whole arc area. Moreover, UHFP-GTAW process has the obviously effect on grain refinement, which can decrease the grain size of the fusion zone. The results also revealed that a significant increase of arc pressure while increasing pulse frequency of UHFP-GTAW, which could improve the depth-to-width ratio of weld beads.

In-Situ Neutron Diffraction Study of Gas Tungsten Arc Welding of a 1018 Plain Carbon Steel

2007 ◽  
Vol 1027 ◽  
Author(s):  
Michael Gharghouri ◽  
Michael J Watson ◽  
David Dye ◽  
Ronald B Rogge
Keyword(s):  
Neutron Diffraction ◽  
Arc Welding ◽  
Neutron Diffraction Study ◽  
Plain Carbon Steel ◽  
Gas Tungsten Arc Welding ◽  
Gas Tungsten Arc ◽  
Gtaw Process ◽  
Gas Tungsten ◽  
In Situ Neutron Diffraction

AbstractIn-situ neutron diffraction measurements of a dynamic Gas Tungsten Arc Welding (GTAW) process have been performed using a unique instrument that establishes steady-state conditions by translating and rotating a cylindrical specimen past a stationary weld torch. The fixed neutron sampling volume is at a constant location with respect to the torch as new material is brought into the fusion zone. We present maps of lattice spacing and integrated intensity as a function of location about the weld torch, which provide insight into the temperature and phase distributions around the weld.

Influence of filler wire addition on weld pool oscillation during gas tungsten arc welding

2004 ◽  
Vol 9 (2) ◽  
pp. 163-168 ◽  
Author(s):  
B. Y. B. Yudodibroto ◽  
M. J. M. Hermans ◽  
Y. Hirata ◽  
G. den Ouden
Keyword(s):  
Weld Pool ◽  
Arc Welding ◽  
Gas Tungsten Arc Welding ◽  
Filler Wire ◽  
Gas Tungsten Arc ◽  
Gas Tungsten

Numerical Model of Melt-Through in a Fully Penetrated GTA Weld Pool

2011 ◽  
Vol 221 ◽  
pp. 622-628
Author(s):  
Peng Cheng Zhao ◽  
Shu Jiang Li
Keyword(s):  
Liquid Metal ◽  
Weld Pool ◽  
Arc Welding ◽  
Mechanical Model ◽  
Bottom Surface ◽  
Welding Parameters ◽  
Quasi Steady State ◽  
Gas Tungsten Arc ◽  
Factors Influencing ◽  
Set Up

A mechanical model of the fully penetrated gas tungsten arc welding (GTAW) weld pool was established to investigate how the melt-through takes place. Analyses show that the forces acting on the liquid metal column which locates in the center of weld pool, whose undersurface and altitude are the bottom surface and thickness of weld pool respectively, determine whether the melt-through occurs. A criterion is set up for judging whether the workpiece will melt through with a specific thickness and selected welding parameters. Factors influencing the melt-through are studied theoretically, and the magnitude and scale of forces that acting on the liquid metal column in a quasi-steady state weld pool are calculated numerically. By using the established criterion, welding currents suitable for a workpiece with specific thickness are predicted.

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