Die life is an important ingredient in cost of forgings, particularly in hot forging. A number of surface hardening techniques are used to improve the die wear life. Surface hardening mainly constitutes surface preparation and its treatment to obtain desired properties.

In this investigation gaseous Ferritic NitroCarburizing was carried on the DIN1.2714 (55NiCrMoV7) and AISI H13 steels that are used to manufacture dies for crankshafts and axle beams.

The compound layer (white layer), diffuse layer and core structure were identified using optical and scanning electron microscopes.

The effect of surface treatment (sand blasting) and process parameters like nitrogen and carbon activities on the formation of different layers during nitrocarburizing are reported and discussed in the paper.

Mainly, the influence of compound layer microstructure on the wear rate with variation in sliding distance, sliding velocity and normal load are reported along with the analysis of wear mechanisms.

Key words: Hot forging dies, Gaseous ferritic nitrocarburizing, White layer, Die wear, Wear mechanisms.