METHOD FOR PRODUCING AN ATMOSPHERE FOR THERMAL TREATMENT BY AIR SEPARATION BY ADSORPTION.

摘要

The invention relates to a process for producing an atmosphere for thermal treatment of metals, formed by providing a gaseous nitrogen stream, according to which a crude gaseous nitrogen stream having a residual oxygen content is first formed by air separation by selective adsorption, to which stream is added a stream of hydrogen at least sufficient to remove, by water vapour formation by catalytic reaction, the essential part of the residual oxygen, characterised in that the following measures are employed in combination: a) the air separation by selective adsorption is carried out so that the gaseous nitrogen stream has a residual oxygen content of between 0.1% and 3%; b) the catalytic reaction to form water vapour is brought about exclusively with catalysts whose use does not involve external application of heat and c) the catalytic reaction to form water vapour is carried out in such a way that the residual oxygen content is less than 30 vpm, with a water vapour content of between 0.2% and 6%, relative to the nitrogen stream, being set up. Exclusive application to the annealing or brazing of copper, decarburising annealing of steels, nitriding of steels, and sintering of copper, nickel, copper-nickel alloys, where appropriate with lead, and copper-zinc alloy.