Investigation of humping defect in high speed gas tungsten arc welding by numerical modelling

Meng, Xiangmeng; Qin, Guoliang; Zou, Zhengguang

doi:10.1016/j.matdes.2016.01.019

Cited by 68 publications

(20 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, as the composition of the shielding gas influences the total arc pressure, this could contribute to the formation of humping [24]. Generally, at high welding currents, the arc pressure causes a marked depression on the weld pool surface [25], forming a thin layer of liquid metal, called the gouging region [20]. The humps start to form when the arc pressure enlarges this region beyond the heat influence of the arc column causing a premature solidification of the thin liquid layer [21].…”

Section: Humping Formationmentioning

confidence: 99%

Effect of shielding gas composition and welding speed on autogenous welds of unalloyed tungsten plates

Marinelli

Martina

Ganguly

et al. 2019

International Journal of Refractory Metals and Hard Materials

View full text Add to dashboard Cite

Tungsten usually exhibits poor weldability and marked brittleness at room temperature. This cause tungsten welds to be affected by the evolution of cracks along the weld bead, which can be eliminated by using a pre-heating step to reduce thermal straining. In this study, based on the tungsten inert gas welding process, a working envelope, focussed on varying welding speed and five different shielding gas mixtures of argon and helium, has been defined with the view of producing crack-free autogenous welds. The bead appearance and the microstructure of the different welds were correlated to the welding parameters, whose main effects have been analysed. Welding defects such as humping occurred when using gas mixtures with relatively low content of helium, and when using relatively high welding speeds. Crack-free autogenous welds have been produced without preheating when using a high content of helium and relatively low welding speeds. Thus, this study has demonstrated that a helium-rich shielding gas is required for welding thick tungsten plates. Moreover, the low thermal shock induced by the process, coupled with the purity of the tungsten plates used, strongly contributed to avoid the occurrence of any crack.

show abstract

Section: Humping Formationmentioning

confidence: 99%

Effect of shielding gas composition and welding speed on autogenous welds of unalloyed tungsten plates

Marinelli

Martina

Ganguly

et al. 2019

International Journal of Refractory Metals and Hard Materials

View full text Add to dashboard Cite

show abstract

“…13A and C. Furthermore, the action of the assisting arc with pulse peak current could reduce the length of the gouging region and suppress the formation of the humping defect, which could be formed with the elongation of the gouging region in high-speed GTA welding (Refs. 29,30).…”

Section: Weld Pool Behaviormentioning

confidence: 99%

High-Speed Tandem Pulsed GTAW of Thin Stainless Steel Plate

2019

View full text Add to dashboard Cite

A novel high-speed welding process with tandem pulsed gas tungsten arcs, which employed two pulse arcs with a 180-deg phase to regulate the behavior of the weld pool and obtain a high-quality weld bead with low welding heat input, was proposed. The effects of pulse welding current parameters on the weld appearance were studied through a statistical design of experiment. The welding speed of a 1.2-mm-thick 304 austenite stainless steel plate can reach up to 3.0 m/min without sacrificing weld appearance quality. The grain structure, mechanical properties, and heat input of tandem pulsed gas tungsten arc welding (GTAW-P) were analyzed and compared with those of single and tandem GTAW. Good mechanical properties of the welded joint were obtained by tandem GTAW-P. Compared with the single and tandem GTAW, the heat input of tandem GTAW-P was decreased by 17.5 and 14.5%, respectively. The main arc at pulse peak obtained sufficient penetration, and the assisting arc at pulse background reduced the unnecessary heat input. When the main arc reached pulse background, the assisting arc at pulse peak heated the trailing region of the molten pool continuously to ensure reflow of the metal and suppressed the generation of weld defects.

show abstract

“…Recently, Pan et al [7,15] investigated the weld pool dynamics and the formation of weld bead during VP-GTAW of aluminum alloy with filler metal. Meng et al [16] studied the undercut and humping defects in high-speed GTAW using numerical modelling. Although some achievements had been made by the previous research, there were still some problems existing.…”

Section: Introductionmentioning

confidence: 99%

Effects of Welding Speed and Pulse Frequency on Surface Depression in Variable Polarity Gas Tungsten Arc Welding of Aluminum Alloy

Zhao

Wei

2019

Metals

View full text Add to dashboard Cite

A three-dimensional (3D) numerical model with the volume of fluid method is developed for high-speed variable polarity gas tungsten arc welding (VP-GTAW) of aluminum alloys. It predicts the thermal flow field in the weld pool, the weld pool surface deformation, and solidified bead geometry during VP-GTAW in successive welding passes. Verification of the numerical model was performed by comparing the calculated results with metallography of welded cross-sections. The prediction showed reasonable accuracy in predicting weld bead geometry. The prediction average relative errors of the bead width and depth of penetration are less than 7%. The deformed weld pool surface, the fluid flow in the weld pool, and maximum fluid temperature in the workpiece based on the developed model, are discussed in detail. The effects of welding speed and pulse frequency on surface depression are studied. The results show that the maximum fluid temperature is closely correlated to the welding speed and pulse frequency. Further, the upper and lower limit of maximum fluid temperature would provide a clue by which the surface depression and the pitch of humps may be recognized. An increase in welding speed will lead to the increase of the pitch of humps, but the reverse is true in the pulse frequency. These detailed physical insights facilitate the prediction of welding surface defects in the high-speed VP-GTAW of aluminum alloy.

show abstract

Investigation of humping defect in high speed gas tungsten arc welding by numerical modelling

Cited by 68 publications

References 27 publications

Effect of shielding gas composition and welding speed on autogenous welds of unalloyed tungsten plates

Effect of shielding gas composition and welding speed on autogenous welds of unalloyed tungsten plates

High-Speed Tandem Pulsed GTAW of Thin Stainless Steel Plate

Effects of Welding Speed and Pulse Frequency on Surface Depression in Variable Polarity Gas Tungsten Arc Welding of Aluminum Alloy

Contact Info

Product

Resources

About