Shielding gas

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

Laser welding method

Abstract: PURPOSE:To lead a laser light to the groove bottom part side of the inside of a light leading path member by making incident the laser light of high energy density state reduced smaller by using a lens on the incident port of the light leading path member inserted between the relatively opposed welding faces of a welding member. CONSTITUTION:A light leading path member 5 is located at specified position approaching to the back plate 13 covering the space between welding faces 3, 4 by the lower end face thereof and the oscillation of a laser light is executed with feeding a shielding gas through a gas flow path 10. The laser light reduced smaller by being condensed by a lens 9 and of a high energy density state is led into a light leading path 6 through an incident port 7 and led to the outgoing port 8 side with performing multiple reflection on the inner face of the light leading path 6. Due to the light leading path 6 inner face being subjected to mirror working the energy density is slightly reduced compared to the incident port 7 in the outgoing port 8 but the energy density to the extent of melting the member of the groove bottom part side exists and the back plate 13 is outgone from the outgoing port 8, a filler wire 12 or metal powder is melted and the deposition of the groove bottom part side between welding faces 3, 4 is enabled.

Weld Distortion Control During Welding Process With Reverse-Side Heating

Abstract: An in-process method for controlling welding, distorsion in filet welds is developed. It particularly reduces angular distortion by performing reverse-side Tungsten inert gas (TIG) heating of the weld line at a fixed distance ahead of metal inert gas (MIG) welding during the weld process. Various heating conditions are examined by experiment and by the finite-element analysis in order to determine appropriate conditions and to study the mechanism by which welding distortion is reduced. It is consequently found that this mechanism is a result of two main effects : TIG heating effect on the reverse side, which produces the opposite angular distortion, and preheating effect.

Method of welding for hard surfacing

Abstract: A method of welding for hard surfacing comprises feeding a powdery mixture, prepared by adding at least one of the powders on NbC, VC, and TiC to the powder of an alloy steel containing either Fe, Ni, and Cr, or Fe and Cr as the chief components, to an arc produced between a base metal of iron or steel and a nonconsumable electrode shielded by an inert gas, and thereby forming a weld metal on the base metal.

Microstructure of laser metal deposited duplex stainless steel: Influence of shielding gas and heat treatment

Abstract: This research work is the first step in evaluating the feasibility of producing industrial components by using Laser Metal Deposition with duplex stainless steel Wire (LMDw). The influence of Ar and N2 shielding gases was investigated in terms of nitrogen loss and in the microstructure and austenite content of different deposited geometries. The evolution of the microstructure in the build-up direction of the Ar and N2-shielded blocks was compared in the heat-treated and as-deposited conditions. The susceptibility for oxygen pick-up in the LMDw deposits was also analyzed, and oxygen was found to be in the range of conventional gas-shielded weldments. Nitrogen loss occurred when Ar-shielding was used; however, the use of N2-shielding prevented nitrogen loss. Austenite content was nearly doubled by using N2-shielding instead of Ar-shielding. The heat treatment resulted in an increase of the austenite content and of the homogeneity in the microstructure regardless of the shielding gas used. The similarity in microstructure and the low spread in the phase balance for the as-deposited geometries is a sign of having achieved a stable and consistent LMDw process in order to proceed with the build-up of more complex geometries closer to industrial full-size components.