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Microstructure and Properties of 15Cr‐5Ni‐1Mo‐1W Martensitic Stainless Steel
Author(s) -
Krishna S Chenna,
Gangwar Narendra Kumar,
Jha Abhay K.,
Pant Bhanu,
George Koshy M.
Publication year - 2015
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.201400035
Subject(s) - materials science , microstructure , austenite , martensite , ultimate tensile strength , metallurgy , precipitation , ductility (earth science) , carbide , precipitation hardening , diffusionless transformation , martensitic stainless steel , transmission electron microscopy , composite material , physics , creep , meteorology , nanotechnology
In the present investigation, 15Cr‐5Ni‐1Mo‐1W martensitic stainless steel was studied for the microstructure and mechanical properties after heat treatment (solution treatment, cryo treatment, and aging). A combination of high strength and ductility was obtained by cryo treatment (−70°C for 2 h), and aging (500°C for 2 h). Transmission electron microscopy (TEM) and X‐ray diffraction (XRD) were employed to identify the phases in the steel. TEM studies have shown the presence of retained austenite and large (Nb,V)C carbides in the martensite matrix after solution treatment. Aging at 500°C for 2 h has shown precipitation of fine Mo 2 C precipitates in the martensite matrix. The increase in strength after cryo treatment and aging is attributed to transformation of retained austenite and precipitation of fine Mo 2 C precipitates, respectively. The yield strength of the steel in aged condition calculated based on the Orowan strengthening is in good agreement with the experimental value considering the softening induced by reversed austenite. The present steel showed yield strength and ultimate tensile strength of 1050 and 1235 MPa, respectively with a ductility of 20.4%. This paper brings out the details of the investigation results and a correlation between microstructure and strength.