Influence of hydrogen content in working gas on growth kinetics of hardened layer at ion nitriding of 16MnCr5 and A290C1M steels

The impact of hydrogen content from 10 to 30% in the mixture of operating gas environment on the growth kinetics and structure of a hardened layer during ion nitriding of martensite and pearlite steels has been studied. It is stated that hydrogen in the vacuum chamber in the range from 10 to 30% contributed to a 1.2-time increase of nitrogen diffusion rate in 16MnCr5 steel and 1.3-time increase in A290C1M steel. The dependence of the hardened layer thickness and microhardness distribution over the depth on the gas environment composition is stated. The structure of the nitrided layer of steels at different hydrogen contents during ion nitriding is studied. (paper)