Carbon redistribution between an austenitic cladding and a ferritic steel for pressure vessels of a nuclear reactor

Pavlovský, J.; Million, B.; Cíha, K.; Stránský, Karel

doi:10.1016/0921-5093(91)90791-k

Cited by 15 publications

(11 citation statements)

References 3 publications

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“…[1] Several researchers have given/developed quantitative models to describe the carbon migration in DMWs. [8,9] However, either the steels are different or the results are not applicable to 5Cr-0.5Mo/21Cr-12Ni DMWs. In the present work, the carbon migration in 5Cr-0.5Mo/21Cr-12Ni DMWs was studied and a quantitative model was given to describe it.…”

Section: Introductionmentioning

confidence: 93%

“…To describe the carbon migration by a quantitative model, C E should be determined first. Pavlovsky et al [8] consider that the carbon activity at the weld interface is approximately held by a + c ϩ a Ϫ c /2, where a + c and a Ϫ c are carbon activities in steels before welding. The values of a + c and a Ϫ c were calculated, according to Reference 18, from the following two equations, respectively.…”

Section: B the Maximum Carbon Concentrationmentioning

confidence: 99%

“…The effective carbon diffusion coefficient D Ϫ in the ferritic steel of the weld involves both the carbon diffusion in ␣-ferrite and the dissolution of carbides in the ferrite carbide mixture; the effective activation enthalpy value for carbon diffusion in ␣-ferrite is 98.2 kJ mol Ϫ1 and that for carbides dissolution is 235.7 kJ mol Ϫ1 . [8] From the equations and diffusion coefficients given, the carbon distribution for various aging times can be calculated. First, we calculated C E by the aforementioned procedure and, if possible, compared it to the experimental data.…”

Section: A Quantitative Model For Carbon Migrationmentioning

confidence: 99%

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Carbon migration in 5Cr-0.5Mo/21Cr-12Ni dissimilar metal welds

Huang

Wang

1998

Metall Mater Trans A

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The carbon migration between a ferritic steel and an austenitic steel was studied in submerged arcwelded 5Cr-0.5Mo/21Cr-12Ni dissimilar metal welds (DMWs) after aging at 500 ЊC for various times and after long-term service in technical practice. The distribution of carbon, chromium, nickel, and iron in the areas around the weld interface was determined by electron probe microanalysis, and the microstructural aspect in the carbon-depleted/enriched zone was characterized by optical microscopy and transmission electron microscopy (TEM). Furthermore, the precipitation sequences and composition characteristics of the carbides were identified by diffraction pattern microanalysis and energy-dispersive X-ray (EDX) microanalysis. It was found (1) that there exists a coherent relationship between intracrystalline M 23 C 6 and the austenitic matrix; (2) that the composition of M 23 C 6 in the carbon-enriched zone is independent of the duration of aging and service; (3) that the maximum carbon concentration is determined by the carbide type, the composition characteristic of precipitated carbides, and the concentration of carbide-forming Cr adjacent to the weld interface in the carbonenriched zone; and (4) that the carbon migration in the 5Cr-0.5Mo/21Cr-12Ni DMWs can be described by a diffusion model.

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Section: Introductionmentioning

confidence: 93%

Section: B the Maximum Carbon Concentrationmentioning

confidence: 99%

Section: A Quantitative Model For Carbon Migrationmentioning

confidence: 99%

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Carbon migration in 5Cr-0.5Mo/21Cr-12Ni dissimilar metal welds

Huang

Wang

1998

Metall Mater Trans A

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“…8(a), a feature of which was indeed observed for weld joints of ferritic-steel/austenitic-steel. 20,21) Since there are sufficient amount of Cr in the SUS304 layer, the Cr 23 C 6 -type carbide particles immediately precipitate at the occasional C-supersaturated area with a high density of nucleation, forming the carbide band region in the SUS304 layer ( Fig. 8(a)).…”

Section: Carbide Formation and Element Diffusion Behav-mentioning

confidence: 99%

Microstructure Evolutions at Severely-deformed Austenite/Martensite Interfaces of a Layer-integrated Steel

et al. 2009

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The microstructure evolution at interfaces of a layer-integrated steel sheet artificially constructed by ductile austenitic stainless (SUS304) and high-strength martensitic (SCM415) steel layers, which were bonded through a cold-rolling and a subsequent annealing at 1 000°C, has been investigated using scanning transmission electron microscopy (STEM) combined with energy dispersive X-ray spectroscopy (EDS). We find that a significant microstructural reconstruction around the SUS304/SCM415 interface has been accomplished during a short-time annealing followed by water-quenching; the resultant microstructures are found to consist of recrystallized austenite and lath martensite grains for the SUS304 and SCM415 layers, respectively. Interestingly, the original SUS304/SCM415 interface appears to migrate and extend into the SUS304 side, an occurrence of which can be reasonably explained by the martensitic transformation across the composition-gradient interface during quenching. These microstructural evolutions fairly account for a microscopic mechanism on how hetero-interface bonding can be achieved via simple cold-rolling/annealing procedures.KEY WORDS: steels; interface structure; scanning transmission electron microscopy; phase transformation; severe plastic deformation.observed microstructural features, we will discuss how the strong-bonding between the austenite/martensite heterointerface can be accomplished during the annealing-quenching procedures. Experimental ProcedureThe multi-layered steel was produced by a cold rolling process with reduction of about 60 % in total thickness, and then annealed at 1 000°C for 1-10 min followed by quenching into water. As shown in Fig. 1, the outer two layers (0.16 mm in thickness after rolled) are composed of commercial-grade stainless steel SUS304, and the inner layer (0.33 mm in thickness after rolled) is composed of commercial-grade martensitic steel SCM415. Compositions of SUS304 and SCM415 are summarized in Table 1. Details of the manufacturing process of the multi-layered steel are described in elsewhere.13) The as-rolled and annealed samples were cut into small pieces, polished by SiC abrasive paper, and thinned by a Gatan PIPS ion mill or focused ion beam system for transmission electron microscopy (TEM) and STEM observations. TEM, STEM, and EDS analysis were performed using a JEOL JEM-2010F field emission gun microscope at acceleration voltage of 200 kV. Composition mapping analysis was constructed by using C-K, O-K, Si-K, Mn-K, Cr-K, Fe-K, Ni-K, and Mo-L lines. Results Microstructure Changes around the InterfaceFigures 2(a)-2(d) show bright-field (BF) STEM images of the SCM415/SUS304 interfaces. For the as-rolled specimen, the microstructures are found to be composed of heavily deformed fine grains both in the SUS304 and SCM415 layers, in which the grains are significantly elongated with large aspect ratios along the roll direction (RD). In particular, the grains in the SUS304 layer, which are composed of deformed austenite and strain induced martensite, exhibit l...

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“…Boiler four-tube leakage happened frequently and was the main reason of forced outage in thermal generator unit leading to huge damage and economic loss [1][2][3][4]. In order to ensure the safe and economic operation of the power plant and avoid similar event happening, it is very significant to carry out cause analysis and provide proper measurements in time.…”

Section: Introductionmentioning

confidence: 99%

Leakage Causes Analysis on a Boiler Enclosure Wall Superheater

Li¹,

He²,

Guan³

et al. 2015

Proceedings of the 2015 International Conference on Materials, Environmental and Biological Engineering

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Abstract. The leakage reasons for a boiler enclosure wall superheater were discussed based on experimental results of macro fracture observation, chemical composition analysis, metallurgical microstructure examination, SEM and EDS analysis. It was presumed that weld flaw firstly formed due to large weld process parameters, then propagated under long period fatigue stress and developed to penetrated crack, leading to final leakage. It was suggested that boiler supervision and four-tube inspection should be enhanced.

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Carbon redistribution between an austenitic cladding and a ferritic steel for pressure vessels of a nuclear reactor

Cited by 15 publications

References 3 publications

Carbon migration in 5Cr-0.5Mo/21Cr-12Ni dissimilar metal welds

Carbon migration in 5Cr-0.5Mo/21Cr-12Ni dissimilar metal welds

Microstructure Evolutions at Severely-deformed Austenite/Martensite Interfaces of a Layer-integrated Steel

Leakage Causes Analysis on a Boiler Enclosure Wall Superheater

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