Microhardness of plasma-nitrided layers of steels after implantation and following heat treatment at temperature of 500-600 degrees C

In this paper results of microhardness testing of plasmatically nitrided la yers after implantation and following isothermal annealing of five types of structural steels and one type of tool steel are presented. Plasmatically nitrided steel samples were isothermally annealed at temperatures of 500, 5 50, and 600 degreesC in time periods of 5, 10, 20, and 40 hours. The result s of microhardness measurements on surfaces and, cross-sections of the spec imens are quantitatively evaluated. It is established that: I, the temperat ure of isothermal annealing of nitrided steel has no effect on microhardnes s of the samples; 2. the time period of isothermal annealing has a weak eff ect on microhardness of the samples; 3. the effect of above-mentioned param eters, i.e, of T and t, is superimposed on the effect of chemical compositi on of the nitrided steel, which is the main factor influencing the microhar dness of the samples after plasma nitridation and the following isothermal annealing.