Residual stresses in the surface layer of M2 steel after conventional and low pressure (‘NITROVAC 79’) nitriding processes

The distribution of residual stresses in the surface layer of M2 steel after conventional and low pressure (‘NITROVAC 79’) nitriding is reported and discussed in this paper. resses depend on the structure of the nitrided layer, which result from the applied nitriding parameters. The optimum structure has been obtained after low pressure nitriding at an ammonia partial pressure p=2×103 Pa. annealing after nitriding at temperatures below the nitriding temperature did not cause any significant changes in residual stress distributions. Annealing temperatures higher than that used in nitriding caused a marked increase of residual stresses in the surface layer of the steel.