Gas shielded ARC welding of nickel based superalloys

Abstract

Nickel-based superalloys such as Inconel alloys 718, 706, 625, and 945 newlineare employed mostly in components of aviation engines, gas turbines, oil and newlinegas, and other industries. Despite their superior weldability, fusion welded newlineInconel 718 joints suffer from metallurgical issues such as secondary phase newlineformation, HAZ liquidation cracking, etc. when subjected to higher heat input newlineduring traditional welding methods. A novel Spin Arc Gas metal arc welding newlineproduces better weld quality due to its low heat input conditions. Inconel newlinesuperalloy components can also be fabricated directly by controlling the heat newlineinput by one of the direct energy deposition additive manufacturing methods newlinecalled wire arc additive manufacturing (WAAM). newlineThe mechanical and metallurgical characteristics of Gas Metal Arc newline(GMA), Gas Tungsten Arc (GTA), spin arc GMA welded Inconel 718 and newlineIncoloy 945 alloy joints were less explored. Though different post weld heat newlinetreatments of Inconel alloys were investigated the mechanical and metallurgical newlinecharacteristics of GMA and GTA and spin arc GMA welded and heat-treated newlineInconel 718 and Incoloy 945 alloys joints were not carried out widely. newlineIn the present fully sponsored research work, the weldability studies of newlineInconel 718 and Incoloy 945 were performed using Spot Varestraint and newlinecircular weldability tests. GMAW, GTAW and Spin arc GMAW of Inconel newline718 and Incoloy 945 were carried out. The welded discs were heat treated using newlinesolution annealing, single- and double-step aging heat treatments. The welded, newlineas well as the heat-treated Inconel super alloys, were characterized to obtain newlinetheir metallurgical and mechanical properties. Inconel 625 alloy was mainly newlineused in oil and gas industries for valve components in order to improve its newlineproperties. newline