DC extended arc plasma nitriding of stainless and high carbon steel

Stainless steel (SS 302) and high carbon steel (HCS) substrates were nitrid ed in a pot type arc plasma furnace in the temperature range 1100-120 degre es C under different gas (Ar, N-2, H-2) mixture configurations for twenty m inutes each. The nitrided surfaces were characterized by XRD, SEM, metallog raphy and microhardness. Depth of the nitride layer grown was found between 40 to 50 mu m. Microhardness for SS 302 was observed to increase by about three to four times but for HCS the increase was not more than two times. T he major compound phases to grow by this method were indentified to be Fe2- 3N(epsilon), (Cr, Fe)N1-x and CrN in case of SS 302 whereas for HCS the pha ses were recognised as Fe2-3N(epsilon), (Cr,Fe)N1-x, Fe2N(xi) and WN. Furth er details about the experiment and characterization of arc plasma nitrided steel are reported and discussed in this paper. (C) 2000 Kluwer Academic P ublishers.