PSI - Issue 42

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2022) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2022) 000–000 Available online at www.sciencedirect.com ScienceDirect

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Procedia Structural Integrity 42 (2022) 42–49

© 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the 23 European Conference on Fracture – ECF23 © 2020 The Authors. Published by B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of 23 European Conference on Fracture - ECF23 Keywords: Fracture toughness; J-R; cooling transients, ASTM E1820 1. Introduction In this study, the testing was performed in the upper shelf region of the transition curve. Physically, upper shelf is defined as the temperature range where brittle fracture cannot occur. The material fails in a ductile manner. Technologically, however, the definition of upper shelf or onset of upper shelf is much more controversial. The upper shelf definition that is probably closest to the physical definition is the plastic fracture transition temperature (FTP) determined with the explosion bulge test, but even then it is related to the tested section size (normally less than 25 Abstract The fracture toughness in the upper shelf a s de ermined with J-R curve . Presently, ther is no data, n r predictions, regarding the J-R curve development during a decreasing thermal transient. In this study, the effect of rapid cooling on J-R c rves is investi ated. Fracture toughness specimens of a rolled steel plate S460 were c oled from 300 °C to the room t mperature at a cooling rate of 2 °C/s determined at the cente l cation of he specimen. The cooli g rat was selected to be in th same ange as during a loss of coolant accident in a nucl ar power plant. The following was concluded: 1 No unstable b ittle fracture in the upper shelf r ion is obs rved fo the investigated material during the cooling transient. 2.) Ba d on the results, when doing st uctural integrity analyzes of therm l t ansients n the upper shelf region, it is recommendable to use the lowest fracture toughness properties in the investigated temperature range, if no other information is available. © 2020 The Authors. Published by E sevier B V. This is an op n acces ar icle unde the C BY-NC-ND lic nse (http://creativecommons.org/licenses/by-nc-nd/4.0/) P er-review und r respon ibility f 23 Europ an Conference on Fracture - ECF23 Keywords: Fracture toughness; J-R; cooling transients, ASTM E1820 1. Introduction I this tudy, the t sting was performed in the upper sh lf region of the transition curve. Physic lly, upper shelf is d fined as the temperature range where brittle fractu e cann t occur. The material fails in a ductile manner. Technologically, however, the definition f up er shelf or o set of upp r shelf is much more controversial. Th upper shelf definition that is r bably closest to the physical definition is the plastic fracture transition temperature (FTP) determined with the explosion bulge test, but even then it is related to the tested section size (normally less than 25 23 European Conference on Fracture - ECF23 The effect of cooling transients on tearing resistance of a rolled steel S. Lindqvist* a , T. Seppänen a , L. Sirkiä a a Research scientist, Kemistintie 3, 02150, Espoo, Finland Abstract The fracture toughness in the upper shelf area is determined with J-R curves. Presently, there is no data, nor predictions, regarding the J-R curve development during a decreasing thermal transient. In this study, the effect of rapid cooling on J-R curves is investigated. Fracture toughness specimens of a rolled steel plate S460 were cooled from 300 °C to the room temperature at a cooling rate of 2 °C/s determined at the center location of the specimen. The cooling rate was selected to be in the same range as during a loss of coolant accident in a nuclear power plant. The following was concluded: 1.) No unstable brittle fracture in the upper shelf region is observed for the investigated material during the cooling transient. 2.) Based on the results, when doing structural integrity analyzes of thermal transients in the upper shelf region, it is recommendable to use the lowest fracture toughness properties in the investigated temperature range, if no other information is available. 23 European Conference on Fracture - ECF23 The effect of cooling transients on tearing resistance of a rolled steel S. Lindqvist* a , T. Seppänen a , L. Sirkiä a a Research scientist, Kemistintie 3, 02150, Espoo, Finland Elsevier

* Corresponding author. Tel.: +358401387256 E-mail address: Sebastian.lindqvist@vttt.fi * Correspon ing author. Tel : +358401387256 E-mail address: Sebastian.lindqvist@vttt.fi

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of 23 European Conference on Fracture - ECF23 2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open acc ss article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of 23 European Conference on Fracture - ECF23

2452-3216 © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the 23 European Conference on Fracture – ECF23 10.1016/j.prostr.2022.12.004