PSI - Issue 42

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ScienceDirect

Procedia Structural Integrity 42 (2022) 1177–1184 Structural Integrity Procedia 00 (2019) 000–000 Structural Integrity Procedia 00 (2019) 000–000

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© 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 Abstract This work conducts an exploratory evaluation of the brittle fracture behavior for a high-strength martensitic steel using conventional three-point bend SE(B) specimens. A primary purpose of this study is to verify the e ff ectiveness of the Master Curve methodology in providing a reliable estimate of the reference temperature ( T 0 ) derived from fracture toughness data sets measured in the ductile to-brittle transition region (DBT) of an ultra high strength, low alloy martensitic steel. Fracture toughness testing conducted on three-point bend SE(B) specimens at di ff erent test temperatures in the DBT region provides the cleavage fracture resistance data in terms of the J -integral at cleavage instability, J c , and its corresponding K Jc -values for the tested material. While this class of ultra high strength steel having a martensitic microstructure is currently beyond the reach of ASTM E1921, the analyses described here show that the predicted normalized curves of median fracture toughness vs. temperature are in good agreement with the experimental measurements. c 2020 The Authors. Published by Elsevier B.V. his is an open access article under the CC BY-NC-ND license (http: // creativec mmons.org / licenses / by-nc-nd / 4.0 / ) r-review under responsibility of 23 European Conference on F acture – ECF23 . Keywords: master curve; reference temperature; fracture toughness; ductile-to-brittle transition temperature; ultra high strength martensitic steel 23 European Conference on Fracture – ECF23 Evaluation of the T 0 reference temperature for an ultra high strength martensitic steel Vitor S. Barbosa a , Claudio Ruggieri a, ∗ a Polytechnic School, University of Sa˜o Paulo, Sa˜o Paulo 05508-030, Brazil Abstract This work conducts an exploratory evaluation of the brittle fracture behavior for a high-strength martensitic steel using conventional three-point bend SE(B) specimens. A primary purpose of this study is to verify the e ff ectiveness of the Master Curve methodology in providing a reliable estimate of the reference temperature ( T 0 ) derived from fracture toughness data sets measured in the ductile to-brittle transition region (DBT) of an ultra high strength, low alloy martensitic steel. Fracture toughness testing conducted on three-point bend SE(B) specimens at di ff erent test temperatures in the DBT region provides the cleavage fracture resistance data in terms of the J -integral at cleavage instability, J c , and its corresponding K Jc -values for the tested material. While this class of ultra high strength steel having a martensitic microstructure is currently beyond the reach of ASTM E1921, the analyses described here show that the predicted normalized curves of median fracture toughness vs. temperature are in good agreement with the experimental measurements. c 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 . Keywords: master curve; reference temperature; fracture toughness; ductile-to-brittle transition temperature; ultra high strength martensitic steel 23 European Conference on Fracture – ECF23 Evaluation of the T 0 reference temperature for an ultra high strength martensitic steel Vitor S. Barbosa a , Claudio Ruggieri a, ∗ a Polytechnic School, University of Sa˜o Paulo, Sa˜o Paulo 05508-030, Brazil Substantial progress has been made in recent years to characterize fracture behavior over the ductile-to-brittle transition (DBT) region and, more specifically, the dependence of fracture toughness data on temperature for ferritic steels. Wallin (1991, 1993, 2002) advanced the viewpoint of a normalized curve describing the dependence of fracture toughness curve on temperature, as typified by the conventional ASME reference curves (American Society of Me chanical Engineers, 2021), to incorporate the e ff ects of specimen size and statistical scatter on fracture toughness data over the DBT region. The procedure, known as the Master Curve approach (Wallin, 1991, 1993; Merkle et al., 1998; Wallin, 2002; McCabe et al., 2005), defines an indexing (or reference) temperature, T 0 , related to the median frac ture toughness of K Jc -values experimentally measured from standard 1T fracture specimens. Several previous studies have shown that the Master Curve methodology is highly e ff ective in describing the dependence of fracture toughness Substantial progress has been made in recent years to characterize fracture behavior over the ductile-to-brittle transition (DBT) region and, more specifically, the dependence of fracture toughness data on temperature for ferritic steels. Wallin (1991, 1993, 2002) advanced the viewpoint of a normalized curve describing the dependence of fracture toughness curve on temperature, as typified by the conventional ASME reference curves (American Society of Me chanical Engineers, 2021), to incorporate the e ff ects of specimen size and statistical scatter on fracture toughness data over the DBT region. The procedure, known as the Master Curve approach (Wallin, 1991, 1993; Merkle et al., 1998; Wallin, 2002; McCabe et al., 2005), defines an indexing (or reference) temperature, T 0 , related to the median frac ture toughness of K Jc -values experimentally measured from standard 1T fracture specimens. Several previous studies have shown that the Master Curve methodology is highly e ff ective in describing the dependence of fracture toughness 1. Introduction 1. Introduction

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.2022.12.150 ∗ Corresponding author. Tel.: + 55-11-3091-5184 ; fax: + 55-11-3091-5350. E-mail address: claudio.ruggieri@usp.br 2210-7843 c 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 . ∗ Corresponding author. Tel.: + 55-11-3091-5184 ; fax: + 55-11-3091-5350. E-mail address: claudio.ruggieri@usp.br 2210-7843 c 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 .