Sensitivity of driving forces on molten pool behavior and defect formation in high-speed gas tungsten arc welding

Abstract The effect of multi-coupled driving forces on molten pool behavior and defect formation in high-current and high-speed gas tungsten arc welding is investigated quantitatively and systematically through combination of sensitivity analysis and experimentally validated numerical modelling. The arc shear stress is the dominant driving force to facilitate free surface deformation of molten pool and backward flow of liquid metal, which masks the effect of Marangoni force. The capillary pressure plays a dominant effect on suppressing free surface deformation. Three dimensionless groups with explicit physical implications are derived to evaluate tendency of high-speed weld bead defect formation using Buckingham π-theorem. The relevant sensitivity analysis shows that arc shear stress and capillary pressure are the most promoting and suppressive factors for defect formation, respectively. High active element concentration induces undercut and humping defects by decreasing capillary pressure.

[1]  P. Masson,et al.  A model comparison to predict heat transfer during spot GTA welding , 2014 .

[2]  Guoliang Qin,et al.  Numerical analysis of undercut defect mechanism in high speed gas tungsten arc welding , 2016 .

[3]  J. Lowke,et al.  Influence of shielding gas composition on arc properties in TIG welding , 2008 .

[4]  Kenneth C. Mills,et al.  Factors affecting variable weld penetration , 1990 .

[5]  Jiangwei Liu,et al.  Numerical investigation of weld pool behaviors and ripple formation for a moving GTA welding under pulsed currents , 2015 .

[6]  William B. Krantz.  Scaling Analysis in Modeling Transport and Reaction Processes , 2007 .

[7]  Suck-Joo Na,et al.  EFFECT OF VARIOUS DRIVING FORCES ON HEAT AND MASS TRANSFER IN ARC WELDING , 1997 .

[8]  P. Mendez.  Order of magnitude scaling of complex engineering problems, and its application to high productivity arc welding , 1999 .

[9]  Manabu Tanaka,et al.  A unified numerical modeling of stationary tungsten-inert-gas welding process , 2002 .

[10]  K. Mills,et al.  Equation to estimate the surface tensions of stainless steels , 2005 .

[11]  V. Voller,et al.  A fixed grid numerical modelling methodology for convection-diffusion mushy region phase-change problems , 1987 .

[12]  Donald Peckner,et al.  Book Review: Handbook of Stainless Steels , 1978 .

[13]  G. Qin,et al.  Investigation of humping defect in high speed gas tungsten arc welding by numerical modelling , 2016 .

[14]  Akira Matsunawa,et al.  Role of Surface Tension in Fusion Welding (Part 2) : Hydrostatic Effect , 1983 .

[15]  Thomas W. Eagar,et al.  Penetration and defect formation in high-current arc welding , 2003 .

[16]  H. W. Kerr,et al.  High speed fusion weld bead defects , 2006 .

[17]  Cheolhee Kim,et al.  Influence of driving forces on weld pool dynamics in GTA and laser welding , 2013, Welding in the World.

[18]  H. Tsai,et al.  Heat transfer and fluid flow in a partially or fully penetrated weld pool in gas tungsten arc welding , 2001 .

[19]  Yong Zhang,et al.  Uniform Design: Theory and Application , 2000, Technometrics.

[20]  J. Gonzalez,et al.  Plasma–weld pool interaction in tungsten inert-gas configuration , 2013 .

[21]  Richard C. Flagan,et al.  The wall shear stress produced by the normal impingement of a jet on a flat surface , 2000, Journal of Fluid Mechanics.

[22]  Choo,et al.  Mathematical modelling of heat and fluid flow phenomena in a mutually coupled welding arc and weld pool , 1991 .

[23]  Stefano Tarantola,et al.  Sensitivity Analysis in Practice , 2002 .

[24]  W. Shimada,et al.  A Study on Bead Formation by Low Pressure TIG Arc and Prevention of Under-Cut Bead , 1983 .