Influence of the carbon content on the phase composition and mechanical properties of P92-type steel

Published on Nov 14, 2015in Physics of Metals and Metallography0.877
· DOI :10.1134/S0031918X15110058
Valeriy Dudko10
Estimated H-index: 10
(Belgorod State University),
Alexandra Fedoseeva11
Estimated H-index: 11
(Belgorod State University)
+ 1 AuthorsRustam Kaibyshev60
Estimated H-index: 60
(Belgorod State University)
Sources
Abstract
The deformation behavior and the microstructure evolution under the creep of 10Kh9V2MFBR steel (Russian analog of the P92 steel) (in wt %, Fe–8.9% Cr–0.05% Si–0.2% Mn–1.9% W–0.5% Mo–0.25% V–0.07Nb–0.08% N–0.01% B) with the standard (0.1%) and lowered (0.018%) carbon contents have been investigated. After the heat treatment, which included normalizing at 1050°C and tempering at 720–750°C, carbides M 23 C 6 and carbonitrides M(C,N) are formed in the 10Kh9V2MFBR steel, while in the 02Kh9V2MFBR steel (modified P92 steel), carbides M 23 C 6, nitrides M 2N, and carbonitrides M(C,N) as well as δ-ferrite (23%) were found. The measurements of hardness and tensile tests at room and elevated temper-atures did not reveal substantial distinctions in the short-term mechanical properties of both steels. The hardness of steels after tempering was 220 HB. At the same time, the creep characteristics of the steels were found to be different. A decrease in the carbon content leads to an increase in the long-term creep strength and creep limit at 650°C for short-term tests with time-to-fracture shorter than 103 h. The time to fracture of steels with various carbon contents is almost the same in long-term creep tests. Factor responsible for such effect of carbon on the creep strength are discussed.
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Abstract The precipitation of the Laves-phase in a low-carbon 9% Cr heat resistant steel was studied under conditions of aging and creep at 923 K. The Laves-phase of Fe2(W,Mo)-type with a ratio of Mo:W of 1:5 was observed on various boundaries in a tempered martensite structure after a long period of aging/creep. The Laves-phase precipitations provided effective stabilization of the tempered martensite lath structure and therefore promoted creep resistance, although their effect on the dislocati...
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