Understanding room temperature deformation behavior through indentation studies on modified 9Cr–1Mo steel weldments

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2012-08, Vol.552, p.419-426
• Main Authors: Das, C.R., Albert, S.K., Bhaduri, A.K., Murty, B.S.
• Format: Article
• Language: English
• Subjects: Applied sciences; Boron; Chromium molybdenum steels; Creep; Cross-disciplinary physics: materials science; rheology; Deformation, plasticity, and creep; Exact sciences and technology; Ferritic stainless steels; Hardness; Heat affected zone; Heat resistant steels; Indentation; Indentation and weldment; Materials science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Microstructure; Physics; Strain rate sensitivity; Structural steels; Sub-structure/sub-grains; Treatment of materials and its effects on microstructure and properties; Weldments
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2012.05.064

► Observance of lath martensite in different regions of P91B and refined microstructure in ICHAZ of P91. ► Uniform depth of indentation in P91B and variable depth of indentation in P91 weldments. ► Uniform strain rate sensitivity in P91B and variable strain rate sensitivity in P91 weldments. ► Indentation creep depths and indentation depths follow similar trends across the weldment. Deformation behavior of boron free (P91) and boron added (P91B) modified 9Cr–1Mo steel weldments was studied at room temperature using an indentation technique. A sub-structure consisting of sub-grains was observed in the inter-critical heat affected zone (ICHAZ), whereas lath martensitic structure was observed in the coarse grain heat affected zone (CGHAZ) of the P91 weldment. Consequently, weldment showed significant variation in hardness as well as strain rate sensitivity in different regions of the HAZs. On the other hand, P91B steel weldment showed small variation in hardness and strain rate sensitivity, which was commensurate with uniform microstructure consisting of lath martensite. These differences in microstructures as well as hardness values also reflected in large variation in creep depth in P91 compared to the small variation in P91B weldment.