Improvement of Surface Properties of 30CrMo12 Steel Using Borocarbonitriding Treatment

Abstract

Thermochemical treatments of low alloyed steels play an essential role in improving the service life of parts under harsh conditions. Often, the treatment uses require technical significant and financial resources. For this reason, the thermochemical treatments in traditional ovens deserve consideration. In present paper, an experimental study on a 30CrMo12 steel uses the technique of borocarbonitriding process, based on the determination of the borocarbonitrided thickness layers and the kinetic constants of diffusion carried out. This nuance is used in manufacturing mechanical parts specifically solicited in fatigue as the transmission gearings in the helicopters’ rotors and the rolling of in aeronautics. Borocarbonitride treatments were performed in the temperature range of 520°C for 8h. The Borocarbonitride modified surface layer samples consist mainly of γ', ε, α, FeB, Fe2B, and Fe3C phases; according to metallographic technique analysis, it seems to be essentially a modification of the austenite matrix. High hardness values are observed in the modified layer with a sharp decrease in matrix values.