Submerged Arc Welding Machine
Submerged Arc Welding (SAW) is a common arc Welding process. It requires a continuously fed consumable solid or tubular (flux cored) electrode. Molten weld and the arc zone are protected from atmospheric contamination by being “submerged” under a blanket of granular fusible flux consisting of lime, silica, manganese oxide, calcium fluoride and other compounds. When molten, the flux becomes conductive and provides a current path between electrode and the job. The thick layer of flux completely covers the molten metal thus preventing spatter and sparks as well as suppressing the intense ultraviolet radiation and fumes that are a part of the SMAW process.
SAW is normally operated in the automatic or mechanized mode, however, semi-automatic (hand held) SAW guns with pressurized or gravity flux feed delivery are available. The process is normally limited to flat or horizontal fillet welding positions. Deposition rates approaching 45kg/hour is possible with this process. This requires constant voltage power source.
Diode based SAW power source has output voltage controllable in steps with no feedback control for voltage or current. Motorized trolley for voltage or current. Motorized trolley is used for carrying the welding head with wire feeder, wire spool and the flux hopper. Displays for welding voltage, current, wire feed speed and the trolley speed are available. These power sources are rated for continuous duty and welds for hours together without stopping.
Thyristorised power source has feedback control for voltage. This also has feature which limits the current to designed level as protection. This type of power source allows step less control of output voltage and maintains the set voltage constant.
Inverterised SAW power source is incorporated with constant voltage/constant current characteristics. They allow step less selection of output voltage. The weld quality is superior with this type of power source.