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σ‐Phase Embrittlement in Some ferritic‐austenitic stainless steels
Author(s) -
Norström L.Å.,
Pettersson S.,
Nordin S.
Publication year - 1981
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.19810120703
Subject(s) - austenite , embrittlement , materials science , metallurgy , molybdenum , phase (matter) , alloy , chromium , microstructure , chemistry , organic chemistry
Four commercially established ferritic‐austenitic stainless steel grades have been investigated with respect to σ‐phase embrittlement by exposure in the temperature interval 700–900 °C. The results illustrate the fact that this type of steels is rather susceptible to such an embrittlement, and this has to be considered when selecting steel grades for different applications. It is also shown that an increased austenite content in fact promotes σ‐phase formation. Molybdenum as alloying element is found to favour σ‐phase much stronger than chromium (4–5 times counted per wt%), hence enlarging the critical temperature range considerably towards higher temperature. Further, a simple “σ‐equivalent” has been developed by which semiquantitative comparisons of the susceptibility to σ‐phase embrittlement might be made between different steel grades, based on their alloy composition.