Submerged Arc Welding Carbon Steel

Submerged arc welding is a well-established process for the welding of carbon steels. It accounts for about 5% of carbon steel welding and this has been steady for many years.

Welding of carbon steel by submerged arc may be carried out with automatic or semi-automatic systems, the latter being ideal for sub-assembly work in shipyards, for instance. Welding is most frequently DCEP to take advantage of the penetration characteristics, but DCEN or AC may be used if the application requires it. The process can be operated as single wire, twin-wire, or with multiple wires, where careful attention must be paid to wire polarity.

Consumable wires may be solid or tubular. Copper-coated solid wires are available in several grades with varying levels of C, Mn and Si, and diameters up to 4 or 6mm as standard. Tubular wires, both basic flux-cored and metal cored are also available in diameters up to 4mm. Metal powders may also be fed into the weld pool to increase productivity or bring about weld metal modification.

Fluxes for carbon steel may be fused or agglomerated, and acid, basic or neutral in nature. Flux and wire combinations will be selected according to the steel composition and the weld properties required.

The main problems are porosity and gas flats, cracking, particularly as carbon content increases, entrapment of slag, and arc blow on DC.

The main safety issues are electrical and hot metal and slag. The process may be dusty during flux handling but welding fume is not normally a problem.