“Flux” is a material required to prevent the formation of oxides, nitrides and other undesirable materials in the weld zone.
The functions of the flux are as follows:
(1) To clean the surface.
(2) To prevent oxidation of the surface, when hot.
(3) To lower surface tension or to allow normal action of metal surface tension.
(4) To promote alloying of metal surface with the solder.
(5) To promote wetting of the surface by the molten surface with the solder.
(6) To create the “shielding gas cloud” during welding about the weldment.
(7) To supply the additions of heat during welding operation.
(8) To improve the quality of “high strength welds”.
(9) To form the slag with metal impurities.
(10) To stabilise the arc.
(11) To retard the cooling of weld.