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Three-Dimensional Numerical Analysis of Weld Pool in GMAW with Fillet Joint

  • Hunchul Jeong
  • Kyungbae Park
  • Sungjin Baek
  • Dong-Yoon Kim
  • Moon-Jin Kang
  • Jungho Cho
Regular Paper
  • 48 Downloads

Abstract

GMA welding is widely used in many different fields such as automotive, shipbuilding and plant industry and its demand is growing day by day because of its high productivity and quality with cost reduction in manufacturing process. Nevertheless, the studies have been reported just a few cases so far due to its difficulties in expressions for the complexity of physical phenomena and in the derivation of the mathematical models. In this research, its complex numerical models including three-dimensional heat flux, arc pressure and electromagnetic force are newly suggested and its validation is proved through the comparison between the experimental and simulation results. Basically, the arc heat flux, arc pressure and Marangoni flow are employed as the boundary conditions. And electromagnetic force and buoyancy are realized as body terms. The governing equations such as the continuity, momentum, VOF and energy equations are adopted as usual simulations. It is, however, that only these equations cannot fulfill all requirements to investigate the behavior of the weld pool in GMA welding. To compensate the insufficient, three-dimensional mathematical model and coordinate transform of arc are newly suggested to reflect the twisted torch angle and arc effective radius change according to the distance from electrode tip. Suggested analysis model is verified through comparison to lap joint fillet GMAW experiment of steel sheets for automotive industry and it shows successful correspondence.

Keywords

Weld pool CFD GMAW Volume of fluid Steel Automotive 

NOMENCLATURE

B

magnetic flux density

CA

concentration coefficent of arc

Cp

specific heat at constant pressure

F

volume fraction occupied by fluid

Fx

force in the x direction

Fy

force in the y direction

Fz

force in the z direction

gz

gravitational acceleration in the z direction

h

enthalpy

hA

convection coefficient

I

welding current

J

current density

Jz

current density in the z dirction

K

thermal conductivity

Lf

latent heat of fusion

n

normal component

P

pressure

PA

arc pressure

qA

heat input by arc

qd

heat input by droplet

rA

effective radius of arc

rd

droplet radius

Rx

coordinate transformation matrix for x axis

Ry

coordinate transformation matrix for y axis

T

temperature

Td

droplet temperature

t

time

Tl

liquidus temperature

Ts

solidus temperature

T

ambient temperature

V

welding voltage

V⃗

velocity vector

x, y, z

coordinate index in local coordinate system

x′, y′, z′

coordinate index in global coordinate system

Greek symbols

β

volume thermal expansion coefficient

γ

surface tension

εs

emissivity

ηA

heat input efficiency by arc

ηd

heat input efficiency by droplet transfer

θ

travel angle for torch

μ

viscosity

μm

magnetic permeability of metal

μ0

magnetic permeability in vaccum

ν

dynamic viscosity

π

circular constant

ρ

density

σ

normal stress

σs

Stefan-Boltzmann constant

τ

shear stress,surface tangential direction

φ

work angle for torch

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Copyright information

© Korean Society for Precision Engineering and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.School of Mechanical EngineeringChungbuk National UniversityChungcheongbuk-doRepublic of Korea
  2. 2.Joining R&D GroupKorea Institute of Industrial TechnologyIncheonRepublic of Korea

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