Topic
Shielding gas
About: Shielding gas is a research topic. Over the lifetime, 6697 publications have been published within this topic receiving 58668 citations.
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Patent•
01 Sep 2008
TL;DR: In this article, a shielding gas (SG) flow controller for an arc welder includes SG input/output with a controllable valve there between, and having a control input, and a controller having a first input receiving a welding signal representing arc current and a gas flow setting controller generating a flow setting output based on the welding signal, representing a desired SG flow.
Abstract: A shielding gas (SG) flow controller for an arc welder includes SG input/output with a controllable valve therebetween, and having a control input, and a controller having a first input receiving a welding signal representing arc current and a gas flow setting controller generating a flow setting output based on the welding signal, representing a desired SG flow. Input and output pressure sensors provide SG input and out pressure to second and third controller inputs, respectively. A flow setting output modifier modifies the flow setting output of the gas flow setting controller based on the SG input/output pressure, the welding signal, and a characteristic of the controllable valve into a control signal input to the control input of the controllable gas valve to maintain a substantially constant SG flow corresponding to the flow setting output substantially independent of actual SG input/output pressures.
27 citations
TL;DR: In this article, a continuous wave Nd:YAG laser was used to weld a Ti-Pb intermetallic compound to obtain interfaces between mixed fusion zone and liquid lead zone during laser welding of Ti6Al4V and lead.
27 citations
TL;DR: In this paper, the influence of the base metal nitrogen and surface-active element concentrations and nitrogen partial pressure in the shielding gas was investigated for autogenous welding of stainless steel, and the weld nitrogen concentration increases with shielding gas nitrogen content at low nitrogen partial pressures, but at higher partial pressures nitrogen absorption is balanced by N2 evolution.
Abstract: This study deals with nitrogen absorption and desorption during the autogenous welding of stainless steel, investigating the influence of the base metal nitrogen and surface-active element concentrations and nitrogen partial pressure in the shielding gas. The weld nitrogen concentration increases with shielding gas nitrogen content at low nitrogen partial pressures, but at higher partial pressures nitrogen absorption is balanced by N2 evolution. This steady-state nitrogen content is not influenced significantly by the base metal nitrogen content in low sulphur alloys, but in high sulphur alloys, an increase in the initial nitrogen concentration causes higher weld nitrogen contents over the entire range of partial pressures evaluated. The weld metal saturation limit is reached at progressively lower shielding gas nitrogen contents as the base metal nitrogen level increases. It is postulated that less nitrogen is required in the shielding gas to reach the saturation limit in the high sulphur alloys because an appreciable fraction of the nitrogen already present in the base metal is prevented from escaping by a higher level of surface coverage. A kinetic model can be used to describe this behaviour. The desorption rate constant decreases with an increase in sulphur content, but the absorption rate constant is not a strong function of the sulphur concentration. The higher rate of nitrogen removal at the onset of steady-state behaviour causes higher-nitrogen alloys to require more supersaturation prior to bubble formation.
27 citations
TL;DR: In this paper, a mathematical model has been developed describing transport phenomena in gas-metal arc welding, where a cylindrical electrode was considered and attention was concentrated on representing the electrodynamic, heat-transfer, and fluidflow phenomena in the plasma column.
Abstract: A mathematical model has been developed describing transport phenomena in gas‐metal arc welding. In the statement of the model a cylindrical electrode was considered and attention was concentrated on representing the electrodynamic, heat‐transfer, and fluid‐flow phenomena in the plasma column. Solutions were generated for the axisymmetric Maxwell’s equations, Navier–Stokes equations, and thermal‐energy balance equation for variable properties. The specific system considered involved the use of an aluminum electrode and argon as the shielding gas. Several current levels were explored and the theoretical predictions of temperatures were found to be in good agreement with spectroscopically measured temperatures. This appears to have been the first time that gas‐metal arc‐welding problems were treated in such a fundamental manner.
27 citations
Journal Article•
TL;DR: In this paper, a collection of well-specified, clear images is presented that illustrates the condition of a steel gas metal arc welding electrode in Ar-2%O{sub 2} shielding gas over a wide range of constant welding currents.
Abstract: A collection of well-specified, clear images is presented that illustrates the condition of a steel gas metal arc welding electrode in Ar-2%O{sub 2} shielding gas over a wide range of constant welding currents The images show that the transition from globular to spray transfer mode occurs over a narrow current range The transition from spray mode to streaming mode is not evident
27 citations