Surface Strengthening of High-Alloyed Martensitic Steel by Staged Nitriding

Abstract

Gas nitriding processes with cyclical rotation of ammonia and ammonia/air atmospheres are suggested for surface strengthening of martensitic Cr-Ni-W-Mo-V steel. One-, two-, and three-staged processes were studied differing by gas atmospheres at the final stage of processes. Microstructure and phase composition of received diffusion layers were examined. Results of microhardness, wear and impact toughness tests are discussed in correspondence with the layers structure.