Porosity formation mechanism and its prevention in laser welding

Matsunawa, Akira; Mizutani, Masami; Katayama, Seiji; Seto, Naoki

doi:10.1533/wint.2003.3138

Cited by 133 publications

(51 citation statements)

References 10 publications

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“…The possible measures to reduce such porosity are to remove hydrogen sources before and during welding or to produce a hydrogen-oversaturated weld fusion zone by rapid solidification. [25,26] Before welding the oxide and contaminated surface layers should be removed from the workpiece and filler metal, and high-grade (low dewpoint) shielding gases should be used. [18,20,25,26] Higher power density at the workpiece keeps the keyhole stable during welding and increases the solidification time, thus allowing hydrogen to escape from the weld pool.…”

Section: Hydrogen Porositymentioning

confidence: 99%

Research and Progress in Laser Welding of Wrought Aluminum Alloys. II. Metallurgical Microstructures, Defects, and Mechanical Properties

Cao

Wallace

Immarigeon

et al. 2003

Materials and Manufacturing Processes

145

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With the wide application of aluminum alloys in automotive, aerospace, and other industries, laser welding has become a critical joining technique for aluminum alloys. In this review, the research and progress in laser welding of wrought aluminum alloys are critically discussed from different perspectives. The primary objective of the review is to understand the influence of welding processes on joint quality and to build up the science base of laser welding for the reliable production of aluminum alloy joints. Two main types of industrial lasers, carbon dioxide (CO 2 ), and neodymiumdoped yttrium aluminum garnet (Nd:YAG), are currently applied but special attention is paid to Nd:YAG laser welding of 5000 and 6000 series alloys in the keyhole (deep penetration) mode. In the preceding article of this review (part I), the laser welding processing parameters, including the laser-, process-, and material-related variables and their effects on welding quality, have been examined. In this part of the review, the metallurgical microstructures and main defects encountered in laser welding of aluminum alloys such as porosity, cracking, oxide inclusions, and loss of alloying elements are discussed from the point of view of mechanism of their formation, main influencing factors, and remedy measures. The main mechanical properties such as hardness, tensile and fatigue strength, and formability are also evaluated.

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Section: Hydrogen Porositymentioning

confidence: 99%

Research and Progress in Laser Welding of Wrought Aluminum Alloys. II. Metallurgical Microstructures, Defects, and Mechanical Properties

Cao

Wallace

Immarigeon

et al. 2003

Materials and Manufacturing Processes

145

View full text Add to dashboard Cite

show abstract

“…Избежать данных недостатков можно путём примене-ния периодического отключения лазерного излучения, что так же ведёт к созданию наиболее благоприятных условий для формирования мелкозернистой структуры. Как пока-зали исследования, проведённые авторами работы [33], в процессе сварки необходимо добиваться условий, при которых будет отсутствовать плазменный факел в парога-зовом канале, который и является причиной пористости и других дефектов структуры (рис. 7).…”

Section: история развития и анализ направлений снижения структурной нunclassified

“…К недостаткам данного метода, по мнению авторов ра-боты [34], следует отнести дефекты структуры металла шва такие как поры и пики, которые обусловлены разви-тием автоколебаний парогазового канала и сварочной ванны [35,36]. В статье [37] предложено стабилизировать сварочную ванну посредством введения сканирующего лазерного луча с амплитудой до 0,5 мм и частотой скани-рования больше 300,0 Гц.…”

Section: история развития и анализ направлений снижения структурной нunclassified

Analysis of existing methods for controlling the structure of the weld metal

Saraev

Лебедев

Novikov

2016

RIJIE

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“…The formation of keyhole pores, including elongated and irregular root ones, is associated with the instability of the keyhole [26,27]. The laser-induced plasma can influence the keyhole stability, and thus, keyhole porosity is a more significant problem in CO 2 laser welding than in YAG and fibre laser welding [28].…”

Section: Introductionmentioning

confidence: 99%

Effect of porosities on tensile properties of laser-welded Al-Li alloy: an experimental and modelling study

Liu

Lee

et al. 2017

Int J Adv Manuf Technol

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Aluminium-lithium (Al-Li) alloys are very attractive for aerospace applications due to their outstanding properties, such as high specific strength, high rigidity and good resistance to corrosion and fatigue, compared to conventional aluminium alloys. The butt joints of Al-Li 2A97-T3 alloy sheet produced by fibre laser welding with ER2319 filler wire were investigated in this paper. Uniaxial tensile tests have been performed to determine the nominal mechanical properties of the joints with and without porosities. In addition, a defect zone was defined in the welded specimens to investigate the effects of porosity on the joint tensile behaviour. The post-weld strength prediction (PWSP) model in a previous study has been extended by including the effects of the porosity in the welds to predict the overall response of the butt joints. The experimental and the modelling results show a good agreement, with the yield strength having a deviation lower than 5%. Both the yield strength and the ductility of the tensile specimens were observed to have decreased with the presence of porosities. The porosities aggravated the inhomogeneous deformation in the weld zone. Higher strain rate was found in the defect area than the remaining weld zone during plastic deformation, as the porosity in the specimen caused inhomogeneous deformation. It was found that this accelerated the failure of the specimen and lowered the global ductility significantly.

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Porosity formation mechanism and its prevention in laser welding

Cited by 133 publications

References 10 publications

Research and Progress in Laser Welding of Wrought Aluminum Alloys. II. Metallurgical Microstructures, Defects, and Mechanical Properties

Research and Progress in Laser Welding of Wrought Aluminum Alloys. II. Metallurgical Microstructures, Defects, and Mechanical Properties

Analysis of existing methods for controlling the structure of the weld metal

Effect of porosities on tensile properties of laser-welded Al-Li alloy: an experimental and modelling study

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