Tempering of martensitic stainless steel with 0.6 w/o nitogen and /or carbon

Abstract

Martensitic stainless high nitrogen steels are used for advanced bearings because of their superior corrosion resistance and hot hardness. Therefore the tempering behaviour of steels SC, SN and SNC with close to 15 w/o Cr, 1 w/o Mo and 0.6 w/o C, N or C+N, respectively, was investigated. Secondary hardening is enhanced by nitrogen, which also increase the content of retained austenite and its resistance to tempering especially in SNC. During tempering ε-, θ- and MγC2-carbides precipitate in SC while ε-, ζ- and M2N-nitrides appear in SN. In SNC carbides and nitrides precipitate separately. Mössbauer spectroskopy revealed clustering of solute atoms in SC and ordering in SN and more so in SNC.