Creep in an electrodeposited nickel

Sklenička, V.; Kuchařová, K.; Kvapilová, Marie; Svoboda, Milan; Král, Pétr; Vidrich, G.

doi:10.1007/s10853-013-7209-9

Cited by 33 publications

(45 citation statements)

References 24 publications

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“…Figure 2 shows that creep exposure of initial state caused slight changes in the LAGBs spacing both in the gauge length and in the area near to the fracture. Similar results were observed also in other works [2,4,8,10] devoted to creep behaviour of initial state and stability of microstructure during isothermal ageing. It was reported that isothermal ageing has negligible eect on subgrain growth by contrast to subgrain signicant growth during creep exposure.…”

Section: Microstructure Observationssupporting

confidence: 91%

“…• C for 10 4 h caused the signicant reduction of creep resistance down to about 10% of initial state and an additional slight reduction of creep resistance after longer ageing for 2 × 10 4 h. Further, creep behaviour was signicantly inuenced by specimen position in the extrados and intrados parts of bends. Microstructure investigation revealed that long-term annealing has negligible eect on high-angle grain boundary spacing and misorientation.…”

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confidence: 93%

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Influence of Long-term Annealing and Hot Bending on Creep of P92 Pipe

Král

Dvořák²,

Kvapilová³

et al. 2015

Acta Phys. Pol. A

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This work is focused on the creep behaviour of the thick-walled hot bended P92 pipe, with an outer diameter of 350 mm and wall thickness of 39 mm, in its dierent parts, namely in straight parts and bends. Selected creep specimens machined from axial section of pipe were thermally aged at 650• C to simulate microstructure degradation typical for long-term service conditions. Subsequent tensile creep tests at constant load were performed at 600• C under 140 MPa and creep behaviour of various structure states was compared. Microstructure was investigated by scanning electron microscopy equipped with electron backscatter diraction. It was found that ageing at 650• C for 10 4 h caused the signicant reduction of creep resistance down to about 10% of initial state and an additional slight reduction of creep resistance after longer ageing for 2 × 10 4 h. Further, creep behaviour was signicantly inuenced by specimen position in the extrados and intrados parts of bends. Microstructure investigation revealed that long-term annealing has negligible eect on high-angle grain boundary spacing and misorientation. By contrast, creep deformation of long-term annealed specimens led to signicant decreasing in high-angle grain boundary spacing and caused a change in the misorientation distribution of boundaries.

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Section: Microstructure Observationssupporting

confidence: 91%

mentioning

confidence: 93%

Influence of Long-term Annealing and Hot Bending on Creep of P92 Pipe

Král

Dvořák²,

Kvapilová³

et al. 2015

Acta Phys. Pol. A

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“…[9] The deterioration is attributed to localized regions near prior austenitic grain boundaries (PAGB) being preferentially recovered through the formation of Z phase at PAGB accompanying the disappearance of one of the main strengthening factors of the finely dispersed carbonitride (MX, where M denotes metallic elements preferentially forming carbide and/or nitride, and X denotes carbon and/or nitrogen) particles, [10,11] besides the scavenging effect of solute elements of W and Mo owing to the grain boundary precipitation of Laves phase. [12,13] It is thus easy to overestimate the long-term strength of these high-strength steels. Kimura et al [14] proposed for this problem that rupture data below 50 pct of proof stress (0.5PS) at test temperatures are used in the analysis.…”

Section: Introductionmentioning

confidence: 99%

Method of Estimating the Long-term Rupture Strength of 11Cr-2W-0.4Mo-1Cu-Nb-V Steel

Tamura

2015

Metall Mater Trans A

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Long-term rupture data of 11Cr-2W-0.4Mo-1Cu-Nb-V steel were analyzed using an exponential equation for stress regarding time to rupture as a thermal activation process. The fitness was compared with the usually employed method assuming power-law creep. In the exponential method, rupture data are classified into several groups according to the thermal activation process; the activation energy, Q; the activation volume, V; then, the Larson-Miller constant, C, values are calculated, and a regression equation is obtained for each data group. The fitness level of the equation was satisfactorily high for each group. The values of Q, V, and C were unusually small for a data group where an unexpected drop in rupture strength was observed. The critical issue is how to comprehend signs of degradation within the short term. We can observe several signs at a creep time of approximately one-tenth of the times of the degradation events. The small values of Q and V indicate that completely softened regions form and creep locally, which is consistent with previous observations. From both metallurgical considerations and the variations of Q and V, it is suggested that the rate of the unexpected drop in strength is mitigated after further long-term creep.

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“…The chromium content at the level of 9% in P91 and P92 steels restricts their use up to a temperature of 580-600°C. Also, the carbon content in 9% Cr steels affects the type of existing precipitations and the form of martensite, which is described in great detail, inter alia, in [7,[9][10][11]. Higher chromium content of 12% in VM12 steel is required to ensure the oxidation and gas corrosion resistance during the operation at above 600°C [7].…”

Section: Introductionmentioning

confidence: 99%

Changes In Properties and Microstructure of High-Chromium 9-12%Cr Steels Due to Long-Term Exposure at Elevated Temperature

Zieliński

Dobrzański

Purzyńska

et al. 2016

Archives of Metallurgy and Materials

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This paper presents the characteristics of the performance of P91 (X10CrMoVNb9-1), P92 (X10CrWMoVNb9-2) and VM12 (X12CrCoWVNb12-2-2) steels used for condition assessment of the pressure components of boilers with supercritical steam parameters. Studies on the mechanical properties, microstructure tests using scanning and transmission electron microscopy, and X-ray analysis of the phase composition of precipitates were performed for selected steels in the as-received condition and after long-term annealing. These steel characteristics are used for the evaluation of the microstructural changes and mechanical properties of the material of components after long-term service. The result of this study is the database of material characteristics representing the mechanical properties related to the microstructure analysis and it can be used for diagnosis of the components of pressure parts of power boilers.Keywords: steel P91, P92, VM12, microstructure, mechanical properties, long-term annealing inspections, and possible repairs are carried out during the boiler's lifetime to ensure safe and failure-free operation of power units. In safety assessment of the pressure equipment in which new creep-resisting steels were used, it is essential that a number of tests should be carried out to allow the evaluation of their condition and suitability for further operation beyond the design work time under further operation conditions [7,8,[12][13][14][15][16][17][18][19].In cooperation with other research centres (Silesian University of Technology, Czestochowa University of Technology, AGH University of Science and Technology in Cracow) as well as the boiler factories Rafako S.A. and SEFKAO S.A. -the leading manufacturers of boilers, the Institute for Ferrous Metallurgy performs the works on the advance and verification testing of new-generation steels for the power industry [2,7,8,19,21,23].This study presents the results of investigations on the mechanical properties in the as-received condition as well as the effect of long-term impact of elevated temperature and stress on the change in properties of 9-12%Cr steel. Test sampleThe test sample was P91 (X10CrMoVNb9-1), P92 (X10Cr-WMoVNb9-2) and VM12 (X12CrCoWVNb12-2-2) steels in the as-received condition after heat treatment and after long-term exposure at elevated temperature. The chemical composition of the examined steels is summarised in Table 1.

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Creep in an electrodeposited nickel

Cited by 33 publications

References 24 publications

Influence of Long-term Annealing and Hot Bending on Creep of P92 Pipe

Influence of Long-term Annealing and Hot Bending on Creep of P92 Pipe

Method of Estimating the Long-term Rupture Strength of 11Cr-2W-0.4Mo-1Cu-Nb-V Steel

Changes In Properties and Microstructure of High-Chromium 9-12%Cr Steels Due to Long-Term Exposure at Elevated Temperature

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