Factors affecting variable weld penetration

Mills, Kenneth C.; Keene, B. J.

doi:10.1179/095066090790323966

Cited by 211 publications

(82 citation statements)

References 6 publications

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“…the power waveform), 38) the surface tension of the molten pool, 8) and the direction of the molten metal flow (Marangoni flow). 35,39,40) Therefore, the content of the weld porosity depends on the factors which trap the bubbles and enhance the bubble floatability.…”

Section: Analysis Of Porosity Formationmentioning

confidence: 99%

Effects of Different Shielding Gases and Power Waveforms on Penetration Characteristics and Porosity Formation in Laser Welding of Inconel 690 Alloy

Kuo

Lin

2007

Mater. Trans.

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A high power Nd-YAG laser was used to perform bead-on-plate (BOP) welding on high viscosity Inconel 690 alloy plates of 3 mm in thickness with three different shielding gases (Ar, He, and N 2 ). Adopting a rectangular laser power waveform, four different peak-base power differentials (ÁP) were applied with a constant average power of 1.5 kW. A comprehensive investigation was performed into the influences of the shielding gas, the flow rate, and the value of ÁP on the characteristics of the resulting welds, including the weld morphology, the penetration depth, the plume volume, and the porosity formation. The results showed that the weld penetration depth, the depth-to-width ratio, the weld surface roughness and the degree of weld spattering all increased with increasing ÁP. The choice of shielding gas had a significant effect on the porosity ratio (P r ) of the weld. The weld formed under Ar shielding had the highest P r , while that formed under N 2 shielding had the lowest. Under He shielding, the gas flow rate had a significant effect on the porosity ratio. However, under the higher density gases of Ar and N 2 , the porosity appeared to be insensitive to the flow rate. Finally, an increased ÁP yielded a significant reduction in P r for the welds with higher porosity.

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Section: Analysis Of Porosity Formationmentioning

confidence: 99%

Effects of Different Shielding Gases and Power Waveforms on Penetration Characteristics and Porosity Formation in Laser Welding of Inconel 690 Alloy

Kuo

Lin

2007

Mater. Trans.

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“…Theoretical studies supplemented with experimental investigations suggest that the weld penetration is dominated by surface tension temperature gradients over the pool [1,2]. The presence of some surface-active species that increase the melt surface tension with temperature induces thermo-capillary flows deep into the weld and results in deeper penetrations.…”

Section: Flux For Tig Welding Efficiency Improvements: Atig (Activatementioning

confidence: 99%

Enhanced Weld Penetrations in GTA Welding with Activating Fluxes Case Studies: Plain Carbon & Stainless Steels, Titanium and Aluminum

Rückert¹,

Perry

Sire

et al. 2014

MSF

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. Abstract. Flux applications prior to the convention Gas Tungsten Arc Welding (GTAW) is known to improve weld penetrations and improve process competitiveness. This paper summarizes the investigations on aluminum, plain carbon steels, stainless steels and titanium. The importance of flux composition, homogeneity and profile of its application are shown to be primordial in determining the weld depth to width ratio of weld pools. The mechanisms that lead to improved penetrations along with some industrial case studies are presented.

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“…He considered that hydraulic jump occurred when molten metal wall jet velocity exceeded a critical value, thus led to humping. Mills and Keene [5] regarded Marangoni convection force as the reason for the humping phenomenon. Arc pressure model was firstly proposed by Paton et al [6] who considered that a balance of pressure exists between arc and weld pool and hump occurred when arc pressure became larger than the metal pressure during SAW.…”

Section: Introductionmentioning

confidence: 99%

Research on Humping Tendency in High Speed Laser Welding of SUS304 Austenitic Stainless Steel

Cai¹,

Wu²,

Gao³

2017

Proceedings of the 2017 International Conference on Material Science, Energy and Environmental Engineering (MSEEE 2017)

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Abstract. In order to prevent humping defects in high speed laser welding, relationship between humping tendency and welding parameters such as laser power, welding speed and shielding gas blowing direction is studied in this paper. It is found that hump will appear periodically when the welding speed exceeds 21m/min. humping tendency is not sensitive to the varieties of laser power but becoming obvious with the increase of the welding speed. The humping tendency is less obvious when gas blows backward instead of forward. The cross-section morphology characteristic of humping is observed. Rayleigh instability model is used to explain the forming mechanism of humping and the relationship between process parameters and humping tendency in high speed laser welding process. It is found that the potential mechanism of humping phenomenon is the break-up of liquid column due to surface tension. When the length-to-width ratio is less than π, humping can be suppressed. To raise the temperature of weld pool can prevent the liquid metal from cooling too fast and is good for liquid metal spreading, thus the humping is suppressed as well.

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Factors affecting variable weld penetration

Cited by 211 publications

References 6 publications

Effects of Different Shielding Gases and Power Waveforms on Penetration Characteristics and Porosity Formation in Laser Welding of Inconel 690 Alloy

Effects of Different Shielding Gases and Power Waveforms on Penetration Characteristics and Porosity Formation in Laser Welding of Inconel 690 Alloy

Enhanced Weld Penetrations in GTA Welding with Activating Fluxes Case Studies: Plain Carbon & Stainless Steels, Titanium and Aluminum

Research on Humping Tendency in High Speed Laser Welding of SUS304 Austenitic Stainless Steel

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