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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TL;DR: In this article, the influence and vector components of the basic forces on the melted metal drop in gas jet shielded welding a moment before the drop transfers from the electrode to the weld pool are considered.
Abstract: A combination of various factors and phenomena determines the quality of the welded joints. The basic role in setting the properties of the welded joints belongs to the processes taking place in the drop of the melted electrode metal. The paper considers the influence and vector components of the basic forces on the melted metal drop in gas jet shielded welding a moment before the drop transfers from the electrode to the weld pool. Methods of calculating the force exerted by a shielding gas jet on the drop of the electrode metal and subject to its dissociation are offered. The frequency and stability of drop transfer to the weld pool increase with the growth of the shielding gas impact force on the electrode metal drop in double jet gas shielding.
25 citations
TL;DR: In this article, the effects of shielding gas composition on the properties and microstructure of single pass weld metals produced by GMA (gas metal arc) groove welding of 950 MPa class steel plates have been investigated.
Abstract: The effects of shielding gas composition on the properties and microstructure of single pass weld metals produced by GMA (gas metal arc) groove welding of 950 MPa class steel plates have been investigated. The shielding gas employed was a mixture of argon (Ar) and carbon dioxide (CO2) (0–25%), and the weld heat input was ∼3 kJ mm. With increasing CO2 content, the hardness of the weld metal decreased from 380 HV to 280 HV, and the absorbed energy of the Charpy impact test decreased from 130 J to 90 J. The microstructures of the weld metal, consisting primarily of low carbon martensite and carbide free bainite, became more bainitic as the CO2 content of the shielding gas was increased. It was also found that the MA constituent, embrittling microstructure, was formed in the granular bainitic area, the volume fraction of which increased with the CO2 content of the shielding gas.
25 citations
TL;DR: In this article, the effects of micro-plasma arc welding on the morphology and quality of stainless steel edge joint welds were investigated and the results indicated that the collimated shape of the low current plasma arc was mainly responsible for the low sensitivity of the weld morphology to variations in the nozzle standoff distances.
Abstract: The effects of the process parameters of micro-plasma arc welding (micro-PAW) on the morphology and quality of stainless steel edge joint welds were investigated. Micro-PAW was applied on type 304 stainless steels to produce an edge joint weld. Welding experiments were carried out for various combinations of arc current, welding speed, arc length, shielding gas, and clamp distance, with all other operating conditions held constant. The experimental results indicated that the collimated shape of the low current plasma arc was mainly responsible for the low sensitivity of the weld morphology to variations in the nozzle standoff distances. The arc voltage increased with increasing quantity of added hydrogen in the argon shielding gas. It was also found that satisfactory edge joint welds can be formed using a clamp distance of 0.35 mm, and that the edge joint penetration on a 0.1 mm thickness stainless steel is about 60% of the clamp distance.
25 citations
Patent•
15 Jul 1969
TL;DR: In this paper, a heat and spatter shield for an arc-welding gun of the type used for applying gas-shielded consumable-electrode arc welding processes is presented.
Abstract: A heat and spatter shield for an arc-welding gun of the type used for applying gas-shielded consumable-electrode arc-welding processes. A shield element insulated from the welding current circuit is attachable to the arc-welding gun so as to be disposed at the downstream end of the current contact tip and extend beyond the downstream opening of the gas nozzle so as to shield the downstream opening of the gas nozzle from metal spatter ejected from the welding operation and from direct heat radiation from the welding arc. At least the core of the shield element is composed of a heat-resistant nonelectrically conductive material. The shield element is disposed in the gas stream and arranged to provide an airfoil effect contributing to formation of the proper flow configuration of the shielding gas. Cylindrical and spherical-type shield elements are disclosed. Various means are disclosed for attaching the shield element to the arc-welding gun.
25 citations
TL;DR: In this paper, the effect of shielding gas composition on phase transformation and the mechanism of pitting corrosion of hyper duplex stainless steel (HDSS) welds was investigated in highly concentrated chloride environments.
Abstract: The effect of shielding gas composition on the phase transformation and the mechanism of pitting corrosion of hyper duplex stainless steel (HDSS) welds was investigated in highly concentrated chloride environments. The resistance to pitting corrosion of a HDSS tube after welding with Ar shielding gas supplemented with N2 was increased due to a decrease of the PREN (Pitting Resistance Equivalent Number) difference between the γ-phase and the α-phase in the weld metal and the heat affected zone. Cr nitrides (Cr2N) were precipitated in the weld metal and the heat affected zone due to a high α-phase content. Cr-depleted zone adjacent to Cr2N decreased the resistance to pitting corrosion.
25 citations