Abstract

Welding and its allied processes represent a fabrication technology of extremely broad scope for metals and, increasingly, nonmetals. Common arc-welding processes include shielded-metal arc, gas–metal arc, flux-cored arc, submerged arc, plasma arc, and gas–tungsten arc welding. Specific power supply and atmospheric shielding characteristics are associated with each of these processes. Laser and electron beam, oxyfuel–gas, resistance, electroslag, and friction are welding processes that do not use an electric arc. Brazing, soldering, plastics joining, and adhesive bonding are technologies allied to welding. The metallurgy of welding processes involves considerations of heat flow and solidification, as well as of the structure and properties of the metals being welded. Selection of welding-process parameters is based on the particular weldability characteristics associated with major alloy groups, including steel, stainless steel, aluminum, magnesium, nickel, titanium, copper, and refractory metals. Design for welding includes joint and weld types, residual stress, and distortion. Industry specifications discuss testing requirements for welds, limits on welding discontinuities, and safety.