Shielded metal arc welding means, it is one type of arc welding process. Where weld joint is produced by heating the work piece with an electrical arc which is produced between shielded or coated electrode and work piece. In this welding process necessary filler metal is obtained from electrode. Coating or flux of electrode is used for shielding the melting metal from atmospheric harmful gas, maintaining arc stability, cleaning weld surface etc.
Shielded metal arc welding principle:
Heat is obtained in shielded metal arc welding from electric arc strike between coated arc electrode and weld metal. If more or less metal deposit and more or less fusion rate is required on weld metal, thus heat variation controlled by higher or lower current. The produced electric arc melts the coated electrode’s end and work piece also. Thus the fusion process is started and the filler material droplets are transferred from coated electrode to weld metals. This molten metal bonded the both work piece which to be weld. The coated of electrode is melt on the molten metal and produced a gaseous shielding and slag for atmospheric gaseous contamination of molten filler metal.
Shielded metal arc welding advantages:
The equipment of this arc welding is comparatively low and portable. It is the simplest welding process. Various type metal can be weld. Highest quality of welding can be obtain and welding operation can be performed in any position.
Shielded metal arc welding applications:
Building and construction used.
In pipe line work it is used.
In ship building workshop.
Boiler and pressure vessel building.
It has large use in automotive industries.