Gas_Tungsten_Arc_Welding

Gas Tungsten Arc Welding 1 FUSION WELDING Fusion welding is a joining process in which the coalescence of metals is accomplished by fusion. The major fusion welding processes are listed below: • Gas welding  Oxyacetylene gas welding (OAW) • Arc welding  Shielded metal arc welding (SMAW)  Gas tungsten arc welding (GTAW)  Plasma arc welding (PAW)  Gas metal arc welding (GMAW)  Submerged arc welding (SAW)  Electroslag welding (ESW) • High-energy beam welding  Electro beam welding (EBW)  Laser beam welding (LBW) 1.1 Gas Tungsten Arc Welding (GTAW) 1.1.1 Description of the Process GTAW consists of an AC/DC arc burning between a non-consumable electrode and the work piece to melt the joint area. The area of the arc is enveloped in a protective gas shield which protects the weld pool and electrode from contamination while allowing a stable arc to be maintained. The filler wire is added either by hand, or in the mechanized process, by feed rollers attached to the torch. 1.1.2 Application Common applications consists of high quality welding on stainless steels; aluminium and its alloys; copper; nickel alloys and rare materials such as titanium and zirconium. Mild steels are welded when full penetration welds are required within certain tolerances, both in size and x-ray quality. Used widely in the aerospace, chemical and nuclear industries. 1.1.3 Electrical Conditions DC (direct current) - most normally used for GTAW welding of stainless steels welding, arc, electrode, region, low, weld, process, high, wire, steels, materials, heat, ferrite, zone, tungsten, surface, specimen, positive, gas, filler, current, alloys, welds, temperature, should, required, quality, pole, per, material, main, lbs, gtaw, fusion, connected, changes, added, speed, prevent, pool, negative, microstructural, metal, joint, heating, grinding, either, dc, contamination, beam