|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Phase Transformations and Microstructural Evolution
||In-situ Analysis of Redistribution of Carbon and Nitrogen during Tempering of Supermartensitic Stainless Steel
||Frank Niessen, Matteo Villa, Frédéric Danoix, John Hald, Marcel A. J. Somers
|On-Site Speaker (Planned)
Supermartensitic stainless steels are lath martensitic steels with ultra-low interstitial content and are based on the Fe-Cr-Ni system. The alloy grade is popular as a low-cost alternative to highly alloyed duplex stainless steels for oil and gas pipeline applications. The strength and toughness of the initially martensitic microstructure is based on formation of reversed austenite from lath martensite during inter-critical annealing. The homogeneity after austenitization, residual stresses from martensite formation and tempering reactions of martensite upon reheating affect the conditions for formation and stabilization of austenite. The redistribution of C and N was thus measured in-situ by correlative use of synchrotron diffraction and atom probe tomography. Interpretation of the evolution of the lattice parameter of martensite during tempering by segregation of C and N yields excellent agreement with results from atom probe tomography. Furthermore, the effect of transformation strains from martensite formation on the lattice parameter is discussed, and found negligible in the present system.
||Planned: Supplemental Proceedings volume