Gas metal arc welding

About: Gas metal arc welding is a research topic. Over the lifetime, 11706 publications have been published within this topic receiving 109555 citations. The topic is also known as: metal active gas welding & GMAW.

Arc welding method

Abstract: An arc-welding method, which comprises: arc-welding objects of welding together along the line of a groove formed between said objects of welding by continuously moving a welding electrode along the line of said groove while reciprocating said welding electrode in the width direction of said groove; characterized by: calculating at prescribed time intervals, for each one reciprocation of said welding electrode in the width direction of said groove, deviations (l-lo) of values (I) of one of arc current and arc voltage from a previously set reference value (lo), for each of left-side deviations (L) and right-side deviations (R) relative to the vertical plane which passes through the center of amplitude of said one reciprocation of said welding electrode and is parallel to the line of said groove; calculating at said time intervals, when said welding electrode moves over the left side of said groove relative to said vertical plane, differences (L-R) between said left-side deviations (L) and the immediately preceding right-side deviations (R), to controllably aligning the center of said amplitude of said one reciprocation of said welding electrode with the center of said groove In the width direction thereof at said prescribed time intervals so that said differences (L-R) become null; and, calculating at said prescribed time intervals, when said welding electrode moves over the right saide of said groove relative to said vertical plane, differences (L-R) between said right-side deviations (R) and the immediately preceding left-side deviations (L), to controllably aligning the center of said amplitude of said one reciprocation of said welding electrode with the center of said groove in the width direction thereof at said prescribed time intervals so that said differences (L-R) become null.

Measuring the process efficiency of controlled gas metal arc welding processes

Abstract: The thermal or process efficiency in gas metal arc welding (GMAW) is a crucial input to numerical models of the process and requires the use of an accurate welding calorimeter. In this paper, the authors compare a liquid nitrogen calorimeter with an insulated box calorimeter for measuring the process efficiency of Fronius cold metal transfer, Lincoln surface tension transfer and RapidArc, Kemppi FastRoot and standard pulsed GMAW. All of the controlled dip transfer processes had a process efficiency of ∼85% when measured with the liquid nitrogen calorimeter. This value was slightly higher when welding in a groove and slightly lower for the RapidArc and pulsed GMAW. The efficiency measured with the insulated box calorimeter was slightly lower, but it had the advantage of a much smaller random error.

Modelling of gas?metal arc welding taking into account metal vapour

Abstract: The most advanced numerical models of gas–metal arc welding (GMAW) neglect vaporization of metal, and assume an argon atmosphere for the arc region, as is also common practice for models of gas–tungsten arc welding (GTAW). These models predict temperatures above 20 000 K and a temperature distribution similar to GTAW arcs. However, spectroscopic temperature measurements in GMAW arcs demonstrate much lower arc temperatures. In contrast to measurements of GTAW arcs, they have shown the presence of a central local minimum of the radial temperature distribution.This paper presents a GMAW model that takes into account metal vapour and that is able to predict the local central minimum in the radial distributions of temperature and electric current density. The influence of different values for the net radiative emission coefficient of iron vapour, which vary by up to a factor of hundred, is examined. It is shown that these net emission coefficients cause differences in the magnitudes, but not in the overall trends, of the radial distribution of temperature and current density. Further, the influence of the metal vaporization rate is investigated. We present evidence that, for higher vaporization rates, the central flow velocity inside the arc is decreased and can even change direction so that it is directed from the workpiece towards the wire, although the outer plasma flow is still directed towards the workpiece. In support of this thesis, we have attempted to reproduce the measurements of Zielinska et al for spray-transfer mode GMAW numerically, and have obtained reasonable agreement.

Material flow in heterogeneous friction stir welding of aluminium and copper thin sheets

Abstract: The aim of this investigation was to study material flow during dissimilar friction stir welding of AA 5083-H111 to deoxidised high phosphorus copper plates of 1 mm thickness. The welds were performed using different tool geometries and welding parameters. The positions of the copper and aluminium plates, relative to the advancing and retreating sides of the tool, were also changed. It was found that the tool geometry and relative position of the plates deeply influence the morphology of the aluminium and copper flow interaction zones, influencing the distribution of both materials in the weld and the formation of intermetallic compounds. The material accumulated under the tool during welding was found as another important aspect determining weld morphology.