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The Submerged Arc Welding (SAW) process involves
formation of an arc between a continuously fed bare wire electrode and the work piece. The process uses a flux to generate
protective gases and slag, and to add alloying elements to the weld pool. A shielding gas is not required. Prior to welding,
a thin layer of flux powder is placed on the work piece surface. The arc moves along the weld line and as it does so,
excess flux is recycled via a hopper. Remaining fused slag layers can be easily removed after welding. As the arc is
completely covered by the flux layer, heat loss is extremely low. This produces a thermal efficiency as high as 60% (compared
with 25% for manual metal arc). There is no visible arc light, welding is spatter-free and there is no need for fume extraction.
SAW is usually operated as a fully mechanized or automatic process, but it can be semi-automatic. Welding parameters,
which include current, arc voltage and travel speed, all affect bead shape, depth of penetration and chemical composition
of the deposited weld metal. Because the operator cannot see the weld pool, reliance must be placed on parameter settings.
There is virtually no restriction on the material thickness, provided the workpiece is suitably prepared. Most commonly
welded materials are carbon-manganese steels, low alloy steels and stainless steels, although the process is capable of welding
some non-ferrous materials with judicious choice of electrode filler wire and flux combinations. In cutting systems and wear reduction applications, the weld is typically made in a machined pocket, and
then ground to a sharp square edge.
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