Submerged Arc Fluxes

Submerged arc fluxes are granular mineral compounds that blanket the arc in submerged arc welding. They protect the molten weld from the atmosphere, stabilise the arc, shape the bead and contribute alloying elements and slag that peels away after cooling. Together with the wire they define the weld metal properties, so flux and wire must be selected as a matched pair following AWS A5.17 designations for carbon steel such as F7A2-EM12K, where F means flux, 7 the tensile level, A the as-welded condition and 2 the impact test temperature.

Fluxes are broadly fused or agglomerated, and acidic, neutral or basic. Basic agglomerated fluxes give lower weld-metal oxygen and better toughness for pressure vessels, offshore and low-temperature service, while neutral fluxes limit alloy pick-up in multi-pass welds. Flux must be dry: re-dry it as the maker advises and keep opened bags covered, since damp flux causes porosity and hydrogen cracking.

Seven Star LLC supplies fluxes together with submerged arc welding wire from LongTeng and Lincoln Electric. Send the wire class, plate grade and required impact temperature to confirm the pairing. Related drying equipment is under electrode drying ovens, and the full group is under welding consumables.