Effect of Machine Pin-Manufacturing Process Parameters by Plasma Nitriding on Microstructure and Hardness of Working Surfaces

This work concerns two stages of research into plasma nitriding (change steel and modification parameters). In the first stage, pins obtained from currently used were compared with made an alternative material available on market, using same process parameters. As a result metallographic tests carried out, in case, presence thin, porous, heterogeneous nitrided layer or its absence was found, core raw state not thermally improved. second small thickness noticeable porosity surface sample but after heat treatment (incorrect Therefore, parameters proposed, terms mixture gases, currents, time, temperature process. result, satisfactory effective obtained, consisting white near-surface zone ε + γ′-type nitrides 8.7 to 10.2 µm, dark internal γ′ nitrides. The continuous, compact, well adhered surface. samples, fine-needle tempering sorbite structure amount fine bainite, which is correct for nitriding, found. most favorable ion gas flow rate (1.5 L/min N; 0.4 H; 0.3 Ar); currents (BIAS—410 V 4.0 A, SCREEN—320 A); time (26 h 35 min); (550 °C).