Shielding gas

About: Shielding gas is a research topic. Over the lifetime, 6697 publications have been published within this topic receiving 58668 citations.

Multiple arc welding device and method

Abstract: Apparatus and method for welding girth joints in pipelines and similar structures, of the general type described and claimed in U.S. Pat. No. 3,806,694, is improved by adding to the normal or conventional head, on its frame, a second or supplemental welding head with its own independent wire electrode, electric power and shielding gas supply. The second head is mounted on an adjustable support for accommodating work pieces of different radius or for varying arc positions. Oscillating means for spreading the molten metal across the width of the joint, as normally provided for the single welding head in the patent mentioned, are adapted to operate the second head as well and to vary its amplitude of movement. Separate means are provided for adjusting the spacing between each head and the work and also for lateral adjustment to align the heads with the plane of the joint. By these means, the number of stations required for a multiple pass operation, on thick wall pipe, for example, may be reduced. By operating two welding heads on each of two or more carriages, welding equipment requirements may be cut nearly in half, with beneficial effects on the weld, due to improved thermal effects. Either head may precede the other; cantilever means provide stability for the head mounted most remotely from the frame.

Numerical analysis of plasma in CO2 laser and arc hybrid welding

Abstract: Lasers and electric arcs are well known heat sources for the welding of a metal. For the sake of a synergic effect, the two sources can be combined and used at the same time. When the two sources are used simultaneously for material processing, complex phenomena are observed, such as the absorption of the laser in arc plasma and a concentration of plasma caused by the metal vapor generated by laser irradiation. In this paper, temperature distributions of plasma for a CO2 laser and arc hybrid welding are calculated and investigated by use of a numerical analysis. Two types of shielding gases are considered. For argon plasma, the CO2 laser is dramatically absorbed; however, for helium gas, there is little absorption of the laser light in the plasma. Therefore, improper welding results can be expected in the case of a CO2 laser and an argon arc. From the analysis, it was shown that the maximum temperature for a CO2 laser and argon arc hybrid plasma is about 30,000 K. It was also noticed that hybrid plasma was concentrated on the position of laser irradiation for helium-shielding gas.

Method of welding titanium alloy parts with titanium insert

Abstract: A method of welding opposite end surfaces of two titanium alloy parts kept in alignment by a high energy-density welding process such as electron beam welding, laser beam welding or TIG arc welding, characterized by closely interposing an insert member of either practically pure titanium or Ti-Al binary alloy containing up to 3 Wt % of Al. Owing to thorough alloying of the inserted titanium with the constituents of the fused base metal, the weld metal in a weld joint obtained by this method is sufficiently high in both strength and toughness. By an optional postwelding heat treatment, the strength of the weld metal can further be enhanced.

Mechanical and Metallurgical Studies in Double Shielded GMAW of Dissimilar Stainless Steels

Abstract: In the present work, a simple arrangement is made to provide double layer shielding gas supply in addition to primary shielding during gas metal arc welding (GMAW) of two dissimilar stainless steels, i.e., AISI 316 and duplex 2205. Influences of double layer shielding in addition to five more process parameters like welding current, voltage, material of the electrode wire, the type of primary shielding gas, and flow rate on joint tensile strength and fusion zone microhardness are studied. An experimental design technique is used to design the experimental conditions and the results are analyzed to observe the influences of each process parameter and their interactions. The tensile strength is more influenced by the electrode material and the type of shielding, whereas current, interaction between current × voltage and current × flow rate significantly influence microhardness. Welding voltage influences both tensile strength and microhardness. Double layer shielding with CO2 as an outer shielding layer hel...

Apparatus and method for performing welding at elevated temperature

Abstract: A welding apparatus includes a workpiece housing having a window therethrough and having a welding access therethrough for a welder to an interior of the workpiece housing. The workpiece housing is metallic with a heat insulation on an internal surface thereof. A lamp heat source is directed through the window and at the workpiece in the interior of the workpiece housing. A gas source delivers a controllable flow of a shielding gas to the interior of the workpiece housing. A temperature sensor senses a temperature of the workpiece within the interior of the workpiece housing. A feedback controller controls the power to the lamp heat source responsive to the temperature of the workpiece. To perform welding, the workpiece is placed into the interior of the workpiece housing so as to have its temperature sensed by the temperature sensor, and the gas source is operated to envelope the workpiece in the shielding gas. The workpiece is heated by powering the lamp heat source responsive to a setpoint input and to the temperature of the workpiece. The workpiece is welded using a welder operating through the welding access.