Improving the Properties of Low-Alloy and Carbon Steel Tools by Cyclic Nitriding

Abstract

Cyclic nitriding characterized by uniform alternation of cycles with high and low nitrogen potential is considered. In the active stage of the process, the surface layer of the steel is saturated with nitrogen, forming a nitride zone. In the passive stage, the nitrides are resorbed and the internal nitriding zone expands. The phase composition of the nitrided layer in У8 and ХВГ tool steels may be regulated so as to increase the wear resistance of the steel and form a smooth hardness gradient over the surface layer. The length of the active and passive stages such that the wear resistance of the steel is 2.5 times greater than in traditional nitriding by ammonia is determined.