Microstructural evolution and change in hardness in type 304H stainless steel during long-term creep

Stress to produce a minimum creep rate of 10−5%/h and stress to cause rupture at 105h for ferritic and austenitic steels and superalloys

“…The 2.25Cr-1Mo steel was subjected to the heat treatment of annealing for 20 min at 930 1C followed by cooling to 720 1C, annealing for 130 min at 720 1C and then cooling in air before creep test, resulting in a microstructure consisting of ferrite and pearlite, where fine M 23 C 6 and needle-like Mo 2 C were precipitated in the ferrite phase. During creep, fine precipitation of M 23 C 6 carbides takes place in the initial stage of creep in the 18Cr-8Ni austenitic steel [13]. In Ni base superalloy U500, fine precipitation of g, takes place from the supersaturated solid solution during creep.…”

Effect of aging on the impact toughness of 25Cr–20Ni–Nb–N steel

“…Although M 23 C 6 can be only metastable, it is always observed in the early stage of precipitation because it nucleates very easily [5]. M 23 C 6 carbides precipitate on grain boundaries when a solution-treated stainless steel is aged isothermally or slowly cooled within the temperature range of 1123-773 K [6]. The precipitates on grain boundaries have an important impact on the toughness.…”

Advanced Austenitic Heat-Resistant Steels for Ultra-Super-Critical (USC) Fossil Power Plants

“…The morphology of MX is not spherical but in quadrate shape. M 23 C 6 carbide can precipitate at grain boundaries when a solution-treated stainless steel is aged isothermally or slowly cooled within the temperature range of 500-900℃ (Tanaka et al, 2001). The Cr-rich phase M 23 C 6 carbide precipitates at grain boundaries of this steel, shown in Fig.8 (c).…”