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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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TL;DR: In this article, metal-cored arc welding process was used for joining of modified 9Cr-1Mo (P91) steel, and welds were completed using two kinds of shielding gases, each composition being 80% Argon+20% CO 2, and pure argon respectively.
24 citations
TL;DR: In this article, a case study was used to evaluate a methodical approach to select welding processes in a productive environment based on market requirements of Quality and Costs, and the results showed that it is possible to select the most suitable welding process to a specific application, taking into account the market conditions of a company.
Abstract: The aim of this work was to propose, apply and evaluate a methodical approach to select welding processes in a productive environment based on market requirements of Quality and Costs. A case study was used. The welds were carried out in laboratory, simulating the joint conditions of a manufacturer and using several welding processes: SMAW, GTAW, pulsed GTAW, GMAW with CO2 and Ar based shielding gases and pulsed GMAW. For Quality analysis geometrical aspects of the beads were considered and for Cost analysis, welding parameters and consumable prices. Quantitative indices were proposed and evaluated. After that, evaluation of both Quality and Costs was done, showing to be possible to select the most suitable welding process to a specific application, taking into account the market conditions of a company.
24 citations
TL;DR: In this article, the authors investigated a controlled short-arc process with a wire feeding speed which varies periodically, using a steel wire and a steel workpiece to produce bead-on-plate welds and determined the radial profiles of the emission coefficients of an iron line and an argon line or an atomic oxygen line.
Abstract: The controlled short-arc processes, variants of the gas metal arc welding (GMAW) process, which have recently been developed, are used to reduce the heat input into the workpiece. Such a process with a wire feeding speed which varies periodically, using a steel wire and a steel workpiece to produce bead-on-plate welds has been investigated. As welding gases CO2 and a mixture of Ar and O2 have been used. Depending on the gas, the properties of the plasma change, and as a consequence the weldseams themselves also differ distinctly. Optical emission spectroscopy has been applied to analyse the plasma. The radial profiles of the emission coefficients of an iron line and an argon line or an atomic oxygen line, respectively, have been determined. These profiles indicate the establishment of a metal vapour arc core which has a broader profile under CO2 but is more focused in the centre for argon. The measured iron line emission was near to its norm maximum in the case of CO2. From this fact, temperatures around 8000 K and a metal vapour molar fraction above 75% in the arc centre could be roughly estimated for this case. Estimations of the electrical conductivity and the arc field indicate that the current path must include not only the metal vapour arc core but also outer hot regions dominated by welding gas properties in the case of argon.
24 citations
Patent•
16 Oct 1981
TL;DR: A welding wire for automatic arc welding, which is particularly suitable for use in build-up welding operation for the purpose of providing hard surface to a metal die, is described in this paper.
Abstract: A welding wire for automatic arc welding, which is particularly suitable for use in build-up welding operation for the purpose of providing hard surface to a metal die. The welding wire consists of a continuous tubular metal casing and a core composition charged in the interior of the casing and comprises such amounts of Ni, Si, B, Nb and C as essential alloying elements that the deposited metal contains at least 40% of Ni, 3-8% of Si, 0.1-0.4% of B, 0.3-1.8% of Nb and 0.2-1.5% of C, all by weight. Preferably, either a practically pure Ni strip or an Fe-Ni alloy strip is used as the material of the casing, and the core composition in the form of a powder mixture contains necessary amounts of Ni, Si, B, Nb and C, optionally with the addition of a small amount of Zr. The deposited metal given by this welding wire has high wear resistance and good antifrictional property and seldom suffers from weld cracks.
24 citations
TL;DR: In this article, a laser lap welding of zinc coated steel using copper is found to be a promising alternative to resistance spot welding, which not only ensures a zero gap, but also assists in reducing violent vaporisation of zinc, the main cause of porosity and spattering during laser welding.
Abstract: Laser lap welding of zinc coated steel using copper is found to be a promising alternative to resistance spot welding. Copper, which acts as an alloying element for zinc, is sandwiched between the lapped sheets in powder form. Such introduction of copper not only ensures a zero gap, but also assists in reducing violent vaporisation of zinc, the main cause of porosity and spattering during laser welding of zinc coated steel. Emission spectroscopy data recorded during the welding experiments validate the effect of copper on zinc vaporisation. Mechanical tests show acceptable results for laser welds made with copper. Moreover, minimal residual copper in the weld zone, and its extended solid solubility in iron due to non-equilibrium processing rules out the possibility of hot cracking. Concerns regarding electrochemical corrosion due to addition of copper in the weld are addressed and the results are found to be favourable. It is further shown that the fatigue life of a laser weld is ∼25% higher than ...
24 citations