Gas WeldingGas welding is a widely used process for welding carbon and alloy steels, but it can also be used for welding stainless steel, cast iron, aluminium, nickel and copper alloys. In many small workshops where 3-phase power is not available or when working on-site, gas welding is still used for many applications. In the hands of a skilled operator the process is all positional. When welding cast iron or copper, where high heat input is important, gas welding is often the preferred process. Oxygen and acetylene are the gases used for this process because of the need for a high localised heat input and because they can more easily be controlled to give a precise neutral flame. Intermediate gases such as MAPP are sometimes used. Carbon, alloy and stainless steels are normally welded without flux, but most other metals need the application of a flux to dissolve the metal oxides and prevent oxidation. Fluxes of different composition are supplied for aluminium, copper and cast iron. It can be difficult to dissolve the oxides on certain stainless steels and fluxes are available if needed. It is important that the correct flux is used. Using the welding process, hard facing and wear resistant alloys can be applied to many metals by melting suitable material onto the component. This process is widely used in maintenance and construction.
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