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 paper, the superplasticity of Inconel718 superalloy was investigated under T = 950°C and initial strain rate with e ˙ = 1.6 × 10 - 4 s - 1, the elongation of InConel718 is 483.6%.
19 citations
TL;DR: In this paper, the effects of nitrogen flow rate on the microstructure and mechanical performance of the cladding layer were studied through an optical microscope, scanning electron microscope (SEM), X-ray diffraction (XRD), Vickers hardness and friction wear testing machine.
Abstract: As an admirable surface improvement method, arc surface cladding has been widely used in various fields. The surface properties of titanium alloy were improved by gas tungsten arc cladding. In the process of arc claddings, a certain amount of nitrogen was added in the shielding gas to form the hard phase of TiN in the cladding layer. Titanium alloy surface was cladded with the same process parameters and different nitrogen flow rate. The effects of nitrogen flow rate on the microstructure and mechanical performance of the cladding layer were studied through an optical microscope, scanning electron microscope (SEM), X-ray diffraction (XRD), Vickers hardness and friction wear testing machine. The results show that the increase of the nitrogen flow rate not only changes the shape of the arc but also forms a large number of TiN hard phases in the cladding layer. With the increase of the nitrogen flow rate, the number of TiN hard phases in the cladding layer increases gradually, which improves the mechanical property of the cladding layer. The Vickers hardness of the cladding layer is much larger than 600 HV and the friction coefficient is 0.419 when the nitrogen rate is 2 L/min.
19 citations
Patent•
18 Dec 1969
TL;DR: In this article, a fusion welding method for steel exceeding 0.4 percent carbon content where all such steel in the article which is integral with the weld surfaces is heated above the upper transformation temperature is presented.
Abstract: A fusion welding method for steel exceeding 0.4 percent carbon content where all such steel in the article which is integral with the weld surfaces is heated above the upper transformation temperature resulting in a superior weld and a sound article absent localized areas of martensite and other detrimental characteristics. Preheating, simultaneous heating, and/or post heating is employed and when an article is preheated, surfaces to be welded are maintained relatively cold to minimize oxidation. Surfaces to be welded are freshly exposed immediately prior to welding and in an extremely rapid sequence of operations and when preheating is employed; surface exposure, preheating and welding steps are carried out in rapid sequence to minimize oxidation. Surfaces are provided with V-shaped configurations novel to resistance upset butt welding.
19 citations
Patent•
15 Apr 1994TL;DR: In this paper, a method and apparatus for welding a branch tube (20) to a header tube (15) includes a fixture (10) having a pair of clamps for supporting the fixture on the header tube.
Abstract: A method and apparatus for welding a branch tube (20) to a header tube (15) includes a fixture (10) having a pair of clamps for supporting the fixture on the header tube. A welding head (25) on the fixture (10) includes a clamp (30) to hold the branch tube (20) in place relative to the header tube (15). The welding head (25) also includes a collet (55) extending into contact with the header tube (15). The header tube, the collet (55) and the welding head (25) form a limited volume chamber (100) that contains shielding gas in the vicinity of the joint (90) between the branch tube (20) and the header tube (15). The welding head (25) includes a mechanism (70,80) for rotating a tungsten welding electrode (85) around the intersection of the branch tube (20) and the header tube (15) to form the welded joint (90).
19 citations
TL;DR: In this article, a comprehensive analysis of the nitrogen containing plasma phase of a gas tungsten welding arc is presented, showing that ionised species dominate close to the electrode, whereas neutral monatomic and diatomic nitrogen are the primary species near the metal surface at plasma temperatures as low as 5000 K.
Abstract: Although nitrogen concentrations at levels much higher than Sieverts' Law predictions during the arc welding of iron and steel are well established, there is currently no commonly accepted methodology to determine this concentration quantitatively. The nature and concentrations of various species in the plasma phase above the weld pool surface are therefore investigated in the present work using both theoretical and experimental techniques. A comprehensive thermodynamic analysis of the nitrogen containing plasma phase of a gas tungsten welding arc shows that ionised species dominate close to the electrode, whereas neutral monatomic and diatomic nitrogen are the primary species near the metal surface at plasma temperatures as low as 5000 K. When oxygen is added to a nitrogen containing plasma, the resulting nitrogen concentration in the weld metal is further enhanced. Definitive proof is provided for a mechanism in which nitrogen and oxygen species interact in the plasma phase at temperatures below...
19 citations