Effect of Sigma Phase on Fracture Behavior of Steels and Weld Joints of Components in Power Industry Working at Supercritical Conditions

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F25870807%3A_____%2F17%3AN0000025" target="_blank" >RIV/25870807:_____/17:N0000025 - isvavai.cz</a>

Result on the web

<a href="https://www.intechopen.com/books/austenitic-stainless-steels-new-aspects/effect-of-sigma-phase-on-fracture-behavior-of-steels-and-weld-joints-of-components-in-power-industry" target="_blank" >https://www.intechopen.com/books/austenitic-stainless-steels-new-aspects/effect-of-sigma-phase-on-fracture-behavior-of-steels-and-weld-joints-of-components-in-power-industry</a>

DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Effect of Sigma Phase on Fracture Behavior of Steels and Weld Joints of Components in Power Industry Working at Supercritical Conditions

Original language description

Chapter deal with the change of the structure and mechanical properties of the austenitic steels after the exposure at temperatures corresponding to the ultra-super critical (USC) and advanced ultra-super critical (A-USC) parameters. The grades TP347HFG, Super 304H and HR3C were chosen in the study as well as their welded joints. Several bend radii corresponding to various amount of plastic deformation were investigated in order to understand relation between cold work plastic deformation, mechanical properties including creep and the structural changes with the special attention to the generation of sigma phase during long-term high temperature exposure. The effect of solution annealing made after cold work on the material properties and structural changes was studied, too. The mechanical properties were studied using small punch test (SPT) and miniaturized tensile tests taken both from straight part and extrados of bends under investigation. Creep properties of either base metal either welded joints were tested and evaluated using standard creep specimens at temperatures 650, 700 and 750 °C. The obtained results confirmed that the mechanical properties and the structure were significantly influenced by the one-year exposure at the working temperature. The presence of σ-phase was confirmed in the extrados part of the tube bends even after thermal exposure without any loading. On the contrary, no sigma phase was identified in the welds and straight parts of tubes. Very positive effect of solution annealing on the retardation of sigma phase precipitation was found, although in the extrados of bent tubes the same heat treatment caused grain coarsening in the regions affected by welding. The results of experiments were compared with other results obtained from analyses of tubes after 100,000 hours of exposure in a USC block where extensive precipitation of sigma phase was also identified. From experimental data, it can be concluded that even small amount of sigma phase causes drop in fracture properties of all steels under investigation.

Czech name

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Czech description

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Type

C - Chapter in a specialist book

CEP classification

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OECD FORD branch

20502 - Paper and wood

Project

<a href="/en/project/LO1203" target="_blank" >LO1203: Regional Materials Science and Technology Centre - Feasibility Program</a><br>

Continuities

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

Publication year

2017

Confidentiality

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

Book/collection name

Austenitic Stainless Steels - New Aspects

ISBN

978-953-51-3701-6

Number of pages of the result

30

Pages from-to

63-92

Number of pages of the book

216

Publisher name

IN TECH D.O.O., Janeza Trdine 9, 51000 Rijeka, Croatia

Place of publication

Rijeka - Chorvatsko

UT code for WoS chapter

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