Microanalytical evaluation of a prototype stainless bearing steel

T. J. Kinkus*, G. B. Olson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


A novel bearing steel composition intended for a space shuttle main engine turbopump application has been designed by computer-aided thermodynamic modelling. Property objectives for the martensitic stainless steel are a doubling of KIC toughness and KISCC stress-corrosion resistance relative to existing bearing steels. The composition is designed to achieve sufficient refinement of M2C carbides to provide the required hardness of RC = 60 at 0.30C, and to achieve a high stability austenite dispersion for transformation toughening. Microanalytical study of the prototype steel of composition Fe-22.5Co-12Cr-8.5Ni- 0.3Mo-0.25V-0.30C has tested key model predictions. STEM microanalysis of extracted Cr and CrMo carbides was used to evaluate solution treatment response between 1100 and 1150°C. Atom-probe microanalysis was employed to measure compositions of fine M2C carbides in cryogenically-formed martensitic material tempered at 500°C to a slightly c raged condition promoting high toughness. The observed composition of (Cr0.88Mo0.03V0.03Fe0.06)2 C0.92 lies between computed values corresponding to coherent and incoherent equilibrium. The prototype steel exceeds the design toughness objectives, giving a KIC toughness of 47 MPa √m at RC = 60.4 hardness.

Original languageEnglish (US)
Pages (from-to)391-396
Number of pages6
JournalSurface Science
Issue number1-3
StatePublished - Apr 15 1992

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry


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