METHOD FOR NITRATION-HARDENING OR NITROCARBURIZING WORK PIECES FROM STEEL ALLOYS

摘要

The invention relates to a method for nitration-hardening work pieces from steel alloys. The aim of the invention is to achieve the highest possible long-term creep and stress rupture resistance of such steel alloys in a minimum of time and with high reliability. To this end, the inventive method comprises the following steps: a) subjecting the work piece to a nitrocarburization method in a salt bath with a cyanate content between 30 % and 80 % until the white layer reaches a thickness of 0.5 to 3 mu m; b) subjecting the work piece to a gas nitriding method at a temperature of between 500 and 600 DEG C, with a low nitride potential being adjusted so that first the white layer disintegrates while enlarging the geometrical surface. In between these two steps the work piece, for example the injection nozzle of a diesel engine, can be treated with an organic acid.