scholarly journals Three-dimensional integro-differential model of unstationary hydrodynamic process in a liquid-metal pool of underwater arc welding

2021 ◽  
Vol 2131 (2) ◽  
pp. 022027
Author(s):  
E Rybalkin ◽  
E Yagyaev ◽  
V Bogutsky ◽  
L Shron
Keyword(s):  
Liquid Metal ◽  
Differential Equations ◽  
Weld Pool ◽  
Arc Welding ◽  
Technical Problem ◽  
Three Dimensional ◽  
Hydrodynamic Process ◽  
Electromagnetic Effect ◽  
Differential Model ◽  
Welding System

Abstract Wet underwater arc welding is now widely used. At the same time, obtaining high-quality welds with this welding method is an urgent scientific and technical problem due to their saturation with hydrogen and oxygen and the formation of pores. One of the promising directions for solving this issue is the use of an external electromagnetic effect on the liquid metal in the weld pool in order to control the movements of the molten metal flows to improve the degassing processes of welded joints. It is possible to estimate the parameters and efficiency of external electromagnetic influence by means of mathematical modeling of related electromagnetic, hydrodynamic and thermal processes occurring in the welding installation. The article proposes a three-dimensional integro-differential model of a non-stationary hydrodynamic process occurring in the liquid metal of a weld pool in an underwater arc welding system with an external electromagnetic effect. For the equations of hydrodynamics boundary value problems are formed, which, using potential theory, are reduced to a system of integro-differential equations for the vorticity function in the volume of a liquid conductor and a simple vector layer on its surface. For a numerical solution, the resulting system of integro-differential equations is approximated by an algebraic system according to the Krylov-Bogolyubov method. This system of equations makes it possible to determine the velocity field in the liquid metal of the weld pool for any welding modes.

Modeling of Three-Dimensional Gas Metal Arc Welding With Groove

2007 ◽  
Author(s):  
J. Hu ◽  
H. L. Tsai
Keyword(s):  
Weld Pool ◽  
Arc Welding ◽  
Filler Metal ◽  
Gas Metal Arc Welding ◽  
Three Dimensional ◽  
Plasma Arc ◽  
Droplet Impingement ◽  
Sulfur Species ◽  
Metal Arc Welding ◽  
Arc Pressure

This article analyzes the dynamic process of groove filling and the resulting weld pool fluid flow in gas metal arc welding of thick metals with V-groove. Filler droplets carrying mass, momentum, thermal energy, and sulfur species are periodically impinged onto the workpiece. The complex transport phenomena in the weld pool, caused by the combined effect of droplet impingement, gravity, electromagnetic force, surface tension, and plasma arc pressure, were investigated to determine the transient weld pool shape and distributions of velocity, temperature, and sulfur species in the weld pool. It was found that the groove provides a channel which can smooth the flow in the weld pool, leading to poor mixing between the filler metal and the base metal, as compared to the case without a groove.

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.

The Oscillation Behaviour of Liquid Metal in Arc Welding

2007 ◽  
Vol 539-543 ◽  
pp. 3877-3882 ◽  
Author(s):  
M.J.M. Hermans ◽  
B.Y.B. Yudodibroto ◽  
Yoshinori Hirata ◽  
G. den Ouden ◽  
I.M. Richardson
Keyword(s):  
Liquid Metal ◽  
Weld Pool ◽  
Arc Welding ◽  
High Speed ◽  
Numerical Models ◽  
Experimental Studies ◽  
Intermediate Step ◽  
Filler Wire ◽  
Research Activities ◽  
Penetration Control

This paper gives an historic overview and new developments of research activities in the field of the oscillatory behaviour of liquid metal in arc welding. Early work focused on the oscillation behaviour of the weld pool in Gas Tungsten Arc Welding (GTAW). Agitated weld pools exhibit specific modes of oscillation, the frequency of which can be measured from the arc voltage data and is conditioned by the geometry of the weld pool and the properties of the liquid metal. Of technological interest is the alteration of the oscillation behaviour for partially and fully penetrated situations, which can be used for penetration control during welding. A logical extension of the research activities was related to the influence of filler wire addition on the oscillation behaviour. An intermediate step towards the description of Gas Metal Arc Welding (GMAW), is the situation of GTAW with cold filler wire supply. It was found that both the liquid weld pool and the pendant liquid droplet at the tip of the filler wire experience an oscillation, which obscures the influence of the individual contributions of both liquid masses on the voltage data. It was shown that online penetration control is still possible, provided that the metal is transferred in an uninterrupted way, i.e. the filler wire flows smoothly into the weld pool. For GMAW, in which detached droplets collide with the weld pool surface, the difficulties are even more prominent. Recent work is related to this issue. Monitoring of the phenomena occurring at the weld pool and the pendant droplet become problematic by means of the voltage data. Observations by means of high-speed video imaging will be discussed. Apart from the experimental studies, efforts are undertaken in numerical simulations of the processes. A good correlation is obtained between experimental data and the results of the numerical models.

Modeling Three-Dimensional Plasma Arc in Gas Tungsten Arc Welding

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
G. Xu ◽  
J. Hu ◽  
H. L. Tsai
Keyword(s):  
Magnetic Field ◽  
Weld Pool ◽  
Current Density ◽  
Arc Welding ◽  
Three Dimensional ◽  
Gas Tungsten Arc Welding ◽  
Plasma Arc ◽  
Gas Tungsten Arc ◽  
Pool Model ◽  
Gas Tungsten

This article presents a three-dimensional (3D) mathematical model for the plasma arc in gas tungsten arc welding (GTAW). The velocity, pressure, temperature, electric potential, current density, and magnetic field of the plasma arc are calculated by solving the mass, momentum, and energy conservation equations coupled with electromagnetic equations. The predicted results were compared with the published experimental data and good agreements were achieved. This 3D model can be used to study a nonaxisymmetric arc that may be caused by the presence of nonaxisymmetric weld pools, joint configurations, and perturbations such as an external magnetic field. This study also provides a method to calculate 3D arc pressure, heat flux, and current density on the surface of the weld pool which, if coupled with a weld pool model, will become a complete model of GTAW.

Three-Dimensional Modeling of Gas Metal Arc Welding of Aluminum Alloys

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
H. Guo ◽  
J. Hu ◽  
H. L. Tsai
Keyword(s):  
Weld Pool ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Three Dimensional ◽  
Welding Process ◽  
Weld Bead ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Metal Arc Welding ◽  
Arc Welding Process

A three-dimensional mathematical model and numerical techniques were developed for simulating a moving gas metal arc welding process. The model is used to calculate the transient distributions of temperature and velocity in the weld pool and the dynamic shape of the weld pool for aluminum alloy 6005-T4. Corresponding experiments were conducted and in good agreement with modeling predictions. The existence of a commonly observed cold-weld at the beginning of the weld, ripples at the surface of the weld bead, and crater at the end of the weld were all predicted. The measured microhardness around the weld bead was consistent with the predicted peak temperature and other metallurgical characterizations in the heat-affected zone.

Three-Dimensional Modeling of Plasma Arc in Arc Welding

2006 ◽  
Author(s):  
G. Xu ◽  
H. L. Tsai
Keyword(s):  
Magnetic Field ◽  
Weld Pool ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Three Dimensional ◽  
Plasma Arc ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling

Most previous three-dimensional modeling work in gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) focuses on the weld pool. Almost all three-dimensional weld pool models are based on the two-dimensional axisymmetric Gaussian assumption of plasma arc pressure and heat flux. In this paper the three-dimensional plasma arc is modeled and results are presented. The velocity, pressure, temperature, current density, and magnetic field of the plasma arc are computed by solving the conservation equations of mass, momentum, and energy, as well as part of Maxwell's equations. This three-dimensional model allows one to study the non-axisymmetric plasma arc caused by external perturbations such as the external magnetic field. It also provides more accurate boundary conditions when modeling the welding pool. The future work is to unify it with the weld pool model and accomplish a complete three-dimensional model of GTAW and GMAW.

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