Brazing flux used together with silver containing filler metals, in brazing applications on steels, stainless steels, cast irons, nickel and nickel alloys, copper and copper alloys. Cleans the surfaces to be joined and helps wetting of the filler metal. Flux residues can be removed by mechanically, by brushing in hot water, by quenching the brazed parts while they are still hot or by pickling solutions.