Journal ArticleDOI
Influence of thermal history on precipitation of hardening phases in tempered martensite 10%Cr-steel X12CrMoWVNbN 10-1-1
G Götz,Wolfgang Blum +1 more
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In this article, the authors studied the effect of tempering of martensitic 10% Cr-steel in the cast and forged version of a forged version by EDX-analysis of extracted precipitates.Abstract:
Precipitation of hardening phases was studied in the cast and the forged version of a tempered martensitic 10% Cr-steel by EDX-analysis of extracted precipitates in the scanning transmission electron microscope. It was found that the type of V-rich precipitates varies with thermal history. Tempering of the martensitic structure at temperatures ≤690 and ≥730 °C produces M 2 X and MX, respectively, as major V-rich phases (M: metallic elements, X: C, N) with M 2 X being lower in V-content and smaller in size than MX. Creep for 7.7 kh at 650 °C changes the major V-rich phase from M 2 X to MX and also leads to local appearance of relatively large particles of modified V-containing Z-phase. The evolution from M 2 X to MX and Z-phase is expected to be accompanied with decrease in creep resistance.read more
Citations
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Evolution of microstructure and deformation resistance in creep of tempered martensitic 9-12%Cr-2%W-5%Co steels
TL;DR: In this paper, the microstructural evolution during creep at 923 K of four tempered martensite 9-12%Cr-steels modified with 2%W and 5%Co was quantified by electron microscopy.
Journal ArticleDOI
Effects of cyclic deformation on subgrain evolution and creep in 9–12% Cr-steels
J.S. Dubey,Hemambar Chilukuru,J.K. Chakravartty,Michael Schwienheer,Alfred Scholz,Wolfgang Blum +5 more
TL;DR: In this article, changes in subgrain structure due to cyclic straining and their effects on the creep behaviour in 12CrMoWVNbN10-1-1 steel were studied.
Journal ArticleDOI
Microstructural characterization, strengthening and toughening mechanisms of a quenched and tempered steel: Effect of heat treatment parameters
TL;DR: In this paper, a quenched and tempered steel for a large bearing ring was investigated, and the results showed that the quenching and the tempering temperatures were the most influential factors on the strength and toughness.
Journal ArticleDOI
A modified Johnson-Cook model for 10%Cr steel at elevated temperatures and a wide range of strain rates
TL;DR: In this paper, a modified J-C model of 10%Cr steel was developed to consider not only the coupling effects of strains, strain rates and temperatures, but also the mechanism of the hardening and the flow softening during whole deformation processes.
Journal ArticleDOI
Coarsening of precipitates and degradation of creep resistance in tempered martensite steels
Hemambar Chilukuru,Karsten Durst,S. Wadekar,Michael Schwienheer,Alfred Scholz,Christina Berger,Karl-Heinz Mayer,Wolfgang Blum +7 more
TL;DR: In this article, three modified Cr steels were investigated for the types, sizes and volume fractions of precipitates, and it was shown that precipitation of V in the form of fine M2X-particles provides high short-term creep resistance, but causes relatively fast degradation of creep resistance due to Ostwald ripening.
References
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Journal ArticleDOI
The effect of long-term creep on particle coarsening in tempered martensite ferritic steels
TL;DR: In this paper, the authors show that the high creep strength of tempered martensite ferritic steels results from the presence of a dislocation network of subgrain boundaries (SGBs) which is stabilized by carbides.
Journal ArticleDOI
Z phase formation in martensitic 12CrMoVNb steel
A. Strang,V. Vodarek +1 more
TL;DR: In this article, the electron diffraction and X-ray microanalysis studies leading to the discovery of this phase, and the conclusion that it is a new form of Z phase enriched in vanadium.
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Metallurgy and creep properties of new 9-12%Cr steels
TL;DR: In this paper, a computer program for calculation of equilibrium phases in the steels can contribute to increased understanding of the microstructure of these steels, e.g. estimation of the risk of δ-ferrite formation, and balancing of the addition of V, Nb and N so M2X formation can be avoided.
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Modelling precipitation sequences in powerplant steels Part 2 – Application of kinetic theory
TL;DR: In this article, a new kinetic theory capable of dealing with the simultaneous precipitation of several phases has been applied to a variety of creep resistant power plant steels and it has been demonstrated that the model has the ability to predict the vast differences in precipitation kinetics reported in the published literature for power plant STEels.
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Evolution of secondary phases 12% Cr steel during quenching and tempering
TL;DR: In this article, the second phase evolution in the 12 wt.% Cr steel was investigated at 1100 and 1330°C and subsequently tempered at 750°C, and it was found that oil quenching from 1100°C leads to formation of autotempered martensite containing intragranular (Fe4Cr)3C and MN particles.