Numerical modeling on the formation process of keyhole-induced porosity for laser welding steel with T-joint

Li, Xibin; Lu, Fenggui; Cui, Haichao; Tang, Xinhua; Wu, Yixiong

doi:10.1007/s00170-014-5609-x

Cited by 54 publications

(23 citation statements)

References 40 publications

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“…These assumptions are often adopted in the previous related research [12][13][14][15]. Under the combination of laser energy, surface tension, thermal buoyancy, gravity and recoil pressure, complex flow phenomena was induced in the emerged weld molten pool.…”

Section: Numerical Modelmentioning

confidence: 99%

“…The volume of fluid (VOF) method [12] was employed to track the keyhole free surface. The governing equation of VOF model is as follows:…”

Section: Governing Equationsmentioning

confidence: 99%

“…where h c is the convective heat transfer coefficient, ε is the materials emission, k b is the Stefan-Boltzmann constant, V evp is the free surface recession speed due to evaporation and calculated following the research achievement of Li et al [12] and Pang et al [24], ∂σ ∂T is the temperature gradient of the surface tension and u, v and w are the components of u ! in the directions of x, y and z, respectively.…”

Section: Boundary Conditionsmentioning

confidence: 99%

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Numerical modelling and experimental verification of thermal characteristics and their correlations with mechanical properties of double-sided laser welded T-joint

Yang

Wang

Zhao³

et al. 2017

Int J Adv Manuf Technol

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In this study, a three-dimensional model was developed to investigate the temperature fields during a doublesided laser welding process of T-joints, and the correlations between the thermal characteristics and the mechanical properties were researched in details. To verify the modelling results, welding experiments were conducted with two different welding parameters and the geometrical dimensions of the weld pool were measured. It was found that there was a good agreement between the calculated and the measured results. The calculated results showed that the temperature profile was bilateral symmetry along the stringer centre, and the temperature gradient became greater as running far from the stringer centre, especially on the skin side. All of the tensile specimens were fractured along the fusion line on the skin panels for the head and the hoop tensile tests. The loss of the alloying elements near the fusion line on the skin side resulted in the lowest micro-hardness value appeared here, and made it to be the weakest region of the welded T-joints. The calculated thermal cycles indicated that the materials closest to the fusion line on the skin side had been staying at higher temperature for a longer time, and which is the essential reason for the fracture behaviour, micro-hardness distribution and alloying elements distribution of the double-sided laser welded T-joint.

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Section: Numerical Modelmentioning

confidence: 99%

“…The volume of fluid (VOF) method [12] was employed to track the keyhole free surface. The governing equation of VOF model is as follows:…”

Section: Governing Equationsmentioning

confidence: 99%

Section: Boundary Conditionsmentioning

confidence: 99%

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Numerical modelling and experimental verification of thermal characteristics and their correlations with mechanical properties of double-sided laser welded T-joint

Yang

Wang

Zhao³

et al. 2017

Int J Adv Manuf Technol

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“…The governing equations used in calculation are given in previous work [25], which is typical in simulations of molten pool. However the special treatment on heat source, bubbles and mass transfer is described in detail as follows.…”

Section: Mathematical Modelmentioning

confidence: 99%

Formation and influence mechanism of keyhole-induced porosity in deep-penetration laser welding based on 3D transient modeling

et al. 2015

International Journal of Heat and Mass Transfer

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“…Numerical simulation methods can use multiple physics models to describe the complex physical phenomena in the molten pool [9,10]. Many of the studies on the susceptibility to solidification cracking during the welding process using thermomechanical modelling focused on the resulting deformation and residual stresses.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigations on Residual Stress in Laser Penetration Welding Process of Ultrafine‐Grained Steel

Liu

et al. 2018

Advances in Materials Science and Engineering

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Weld solidification crack prevention in the laser penetration welding process is essential for the strength of the welded component. The formation of solidification cracks can ultimately be attributed to welding residual stresses, and preventive measures should be taken during welding. In this study, the effects of residual stresses on the laser penetration welding quality of ultrafine-grained steels were investigated. A heat source model was established through the analysis of the metallography of the cross section of the heat-affected zone (HAZ) of ultrafine-grained AN420s-grade steel, and the chemical composition of the weld bead was obtained using an FLS980-stm Edinburgh fluorescence spectrometer. Furthermore, the constitutive coupling relation between the temperature and material flow stress was established based on the Gibbs function, and the welding residual stress was obtained by setting trace points in a finite element analysis (FEA) model based on experimental data of the weld bead cross section under different welding conditions. The results show that weld solidification cracks will form when the residual stresses exceed the material flow stresses in the weld bead, and the residual stresses can be decreased through a reasonable increase of the welding speed. The results indicate that the proposed criterion has high accuracy and can be used to predict the formation of weld solidification cracks in the laser penetration welding process.

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Numerical modeling on the formation process of keyhole-induced porosity for laser welding steel with T-joint

Cited by 54 publications

References 40 publications

Numerical modelling and experimental verification of thermal characteristics and their correlations with mechanical properties of double-sided laser welded T-joint

Numerical modelling and experimental verification of thermal characteristics and their correlations with mechanical properties of double-sided laser welded T-joint

Formation and influence mechanism of keyhole-induced porosity in deep-penetration laser welding based on 3D transient modeling

Numerical Investigations on Residual Stress in Laser Penetration Welding Process of Ultrafine‐Grained Steel

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