Numerical Simulation of Droplet Transfer with TiO2 Flux Column During Flux Cored Arc Welding by 3D Smoothed Particle Hydrodynamics Method

Abstract

A molten metal droplet transfer processes were simulated by a numerical model using a three-dimensional smoothed particle hydrodynamics method in order to clarify the flux column formation mechanism at the tip of a wire during a flux cored arc welding process. This study focuses on the flux cored arc welding with TiO2 based wire. As a result, although the average droplet size obtained by the computation was larger than that by the experiment, the average length of the flux column obtained by the computation showed agreement with that by the experiment, which supports supported validity of this computational model. Moreover, the melting rate of the metal-pipe around flux was higher than flux. The flux column was formed at the tip of the wire. The simulations with different values of a specific heat and a thermal conductivity were performed to investigate the effect of the heat conduction in the wire on the flux column formation. The unmelted flux column was formed at the tip of the wire when the specific heat of the flux component was smaller and the thermal conductivity was higher than those of TiO2. The result indicated that the heat conduction in flux played an important role in the flux column formation during flux cored arc welding.

Progress of computational plasma fluid mechanics

“…We have applied this incompressible SPH method to the thermofluid simulations of molten metal flows in several kinds of arc welding processes such as GTA weding, 133,134) GMA welding, [135][136][137][138][139] SA welding, 140,141) and Flux-Cored Arc (FCA) welding. 142) Because this incompressible SPH method offers high adaptability for other types of metal processing, it has also revealed the molten metal formation processes with convective and diffusive heat transports during dissimilar Resistance Spot (RS) welding 143,144) and Electroslag (ES) welding 145) collaborating with the experiments, 146,147) and dross formation during gas cutting. 148) 4.3.…”

“…This section presents a computational demonstration of a flux column formation and droplet transfer at a TiO 2 -based wire in FCA welding, using the incompressible SPH method. 142) The diameters of the whole wire and the flux region were set to be 1.2 mm and 0.54 mm, respectively. The wire feed rate was set at 16 m min −1 .…”

“…The details of the computational conditions are found in the literature. 142) Figures 8(a) and 8(b) depict the metal vapor fraction and temperature distributions in and around the arc plasma, which was obtained by a preliminary grid-based steady simulation in a 2D axisymmetric frame. Typical distributions for GMA welding were obtained.…”

“…The more discussion with the detailed description of the experiment is found in the original literature. 142)…”

Particle simulation of nugget formation process during steel/aluminum alloy dissimilar resistance spot welding and thickness estimation of intermetallic compounds

“…ティグ溶接やミグ溶接の溶融池対流現象 [10][11][12][13] ，ミグ溶接やフ ラックスコアードアーク溶接の溶滴移行現象 14,15) ，サブマー ジアーク溶接現象 16) などの溶接・接合分野においても応用 されており [17][18][19][20][21]…”