Crack Analysis in Welds of Boiler Tubes Made of T24 Steel

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F47718684%3A_____%2F25%3A10002953" target="_blank" >RIV/47718684:_____/25:10002953 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.scientific.net/MSF.1166.31" target="_blank" >https://www.scientific.net/MSF.1166.31</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.4028/p-9HzbjV" target="_blank" >10.4028/p-9HzbjV</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Crack Analysis in Welds of Boiler Tubes Made of T24 Steel

Popis výsledku v původním jazyce

The paper deals with the material analysis of cracks in welded joints of tubes made of T/P24 steel of membrane wall panels of superheater from a boiler of a thermal power plant operating in supercritical conditions of inlet steam. A total of ten cracks were evaluated, mainly from longitudinal assembly welds tube - flag. Using light microscopy and scanning electron microscopy, the macrostructure and microstructure of cross-sections of the tubes were observed, HV1 hardness profiles were measured and fractographic analysis of fracture surfaces of cracks was performed. Cracks are initiated on the outer surface of tubes, dominantly on the heated side of the boiler at the interface of the weld metal and the coarse-grained zone of the heat-affected zone of the base material of the tube. They grow more or less in straight course towards the inner surface of the tube. The initiation area is characterized by very coarse prior austenitic grain and secondary hardening leading to hardnesses of around 400 HV1.The cracks were probably formed by several mechanisms – relaxation cracking and fatigue. Theformation of the crack was influenced by a combination of several negative factors: suboptimalwelding process leading to defects in welds, unfavorable microstructure state associated with highhardness, high level of residual stresses and stresses induced by temperature changes duringshutdowns and start-up of boiler.

Název v anglickém jazyce

Crack Analysis in Welds of Boiler Tubes Made of T24 Steel

Popis výsledku anglicky

The paper deals with the material analysis of cracks in welded joints of tubes made of T/P24 steel of membrane wall panels of superheater from a boiler of a thermal power plant operating in supercritical conditions of inlet steam. A total of ten cracks were evaluated, mainly from longitudinal assembly welds tube - flag. Using light microscopy and scanning electron microscopy, the macrostructure and microstructure of cross-sections of the tubes were observed, HV1 hardness profiles were measured and fractographic analysis of fracture surfaces of cracks was performed. Cracks are initiated on the outer surface of tubes, dominantly on the heated side of the boiler at the interface of the weld metal and the coarse-grained zone of the heat-affected zone of the base material of the tube. They grow more or less in straight course towards the inner surface of the tube. The initiation area is characterized by very coarse prior austenitic grain and secondary hardening leading to hardnesses of around 400 HV1.The cracks were probably formed by several mechanisms – relaxation cracking and fatigue. Theformation of the crack was influenced by a combination of several negative factors: suboptimalwelding process leading to defects in welds, unfavorable microstructure state associated with highhardness, high level of residual stresses and stresses induced by temperature changes duringshutdowns and start-up of boiler.

Druh

J_ost - Ostatní články v recenzovaných periodicích

CEP obor

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OECD FORD obor

20501 - Materials engineering

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

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

Název periodika

Materials Science Forum

ISSN

1662-9752

e-ISSN

—

Svazek periodika

2025

Číslo periodika v rámci svazku

1166

Stát vydavatele periodika

CH - Švýcarská konfederace

Počet stran výsledku

7

Strana od-do

31-37

Kód UT WoS článku

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EID výsledku v databázi Scopus

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