SAWOK Grain 21.85 is a non-alloyed metal powder which is added to the SAW process in order to increase the deposition rate. The powder is melted by the heat of the arc. Either the powderis fed in front of the arc (option a) or it is transported by magnetic force, into the arc, along with the wire(option b). It is added to various flux - wire combinations, of which OK Flux 10.62/OK Autrod 12.32 is the most common. The penetration is reduced, because part of the heat is utilised to melt the powder. The process requires all parameters, including the metal powder feeding rate on the additional equipment, to be carefully controlled. The powder feeding rate is regulated by the use of a potentiometer which controls the speed of the bucket wheel and the gap between the tube and the bucket wheel. A skilled welding machine operatoris needed who is capable of steering the additional powder feed unit. Deposition rateincreases up to 100% can be achieved. Submerged arc welding with metal powder addition remains a special process, but with tempting productivity benefits.
