A Novel Decarburizing-Nitriding Treatment of Carburized/through-Hardened Bearing Steel towards Enhanced Nitriding Kinetics and Microstructure Refinement

Decarburization is generally avoided as it reckoned to be a process detrimental material surface properties. Based on the idea of duplex engineering, i.e., nitriding case-hardened or through-hardened bearing steels for enhanced performance, this work deliberately applied decarburization prior plasma cancel softening effect decarburizing with and at same time significantly promote kinetics. To manifest applicability innovative process, low-carbon M50NiL high-carbon M50 were adopted in work. The influence microstructures growth kinetics nitrided layer over decarburized investigated. metallographic analysis thickness indicates that high carbon content can hinder layer, but if short nitriding, promoted. shows reduces activation energy nitrogen diffusion enhances diffusivity. Moreover, air microstructure refinement via spinodal decomposition during nitriding.