Effect of PWHT on microstructure and creep properties of homogeneous welds made of HR3C steel

Kód výsledku v IS VaVaI

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RIV/26722445:_____/19:N0000086

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Effect of PWHT on microstructure and creep properties of homogeneous welds made of HR3C steel

Popis výsledku v původním jazyce

There are high demands placed on ensuring the integrity when building blocks of fossil power plants with USC steam parameters. Weld joints are critical parts of fossil power units. At present, the behaviour of the new austenitic steels such as HR3C (X6CrNiNbN 25-20) is not sufficiently described. The paper deals with the effect of Post-Weld Heat Treatment (PWHT) at 1230 °C on both creep behaviour and microstructure evolution in homogeneous weld joints made of modern austenitic steel HR3C. Stress rupture tests were performed on the cross-weld joints of tubes ø 38 x 6.3 mm at 700 °C with times to rupture up to nearly 22,000 hours. The structural changes after long-term creep exposure were studied on longitudinal sections by various microscopic techniques. The stress rupture test results of welds after PWHT revealed their higher creep resistance when compared to the As-Welded state (AW). The calculated creep rupture strength at 700 °C/100,000 hours of BM and weld joint after PWHT are almost the same, while. The AW samples as opposed to PWHT samples did not show a noticeable growth of the austenitic grain size in Heat-Affected Zone (HAZ). In specimens after PWHT the average grain size in HAZ was more than twice that of BM. The aim of this paper is to study the microstructure and creep behaviour of the homogeneous HR3C weld joints in two states, both after welding and after post-weld heat treatment.

Název v anglickém jazyce

Effect of PWHT on microstructure and creep properties of homogeneous welds made of HR3C steel

Popis výsledku anglicky

There are high demands placed on ensuring the integrity when building blocks of fossil power plants with USC steam parameters. Weld joints are critical parts of fossil power units. At present, the behaviour of the new austenitic steels such as HR3C (X6CrNiNbN 25-20) is not sufficiently described. The paper deals with the effect of Post-Weld Heat Treatment (PWHT) at 1230 °C on both creep behaviour and microstructure evolution in homogeneous weld joints made of modern austenitic steel HR3C. Stress rupture tests were performed on the cross-weld joints of tubes ø 38 x 6.3 mm at 700 °C with times to rupture up to nearly 22,000 hours. The structural changes after long-term creep exposure were studied on longitudinal sections by various microscopic techniques. The stress rupture test results of welds after PWHT revealed their higher creep resistance when compared to the As-Welded state (AW). The calculated creep rupture strength at 700 °C/100,000 hours of BM and weld joint after PWHT are almost the same, while. The AW samples as opposed to PWHT samples did not show a noticeable growth of the austenitic grain size in Heat-Affected Zone (HAZ). In specimens after PWHT the average grain size in HAZ was more than twice that of BM. The aim of this paper is to study the microstructure and creep behaviour of the homogeneous HR3C weld joints in two states, both after welding and after post-weld heat treatment.

Druh

D - Stať ve sborníku

CEP obor

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OECD FORD obor

20501 - Materials engineering

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

Metal 2019 Conference Proceedings

ISBN

978-80-87294-92-5

ISSN

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e-ISSN

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Počet stran výsledku

6

Strana od-do

810 - 815

Název nakladatele

Tanger Ltd., Ostrava

Místo vydání

Ostrava

Místo konání akce

Brno

Datum konání akce

19. 5. 2019

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

999