University of Oulu

Renata Latypova, Tun Tun Nyo, Oskari Seppälä, Eric Fangnon, Yuriy Yagodzinskyy, Saara Mehtonen, Hannu Hänninen, Jukka Kömi, Sakari Pallaspuro, Effect of prior austenite grain morphology on hydrogen embrittlement behaviour under plastic straining in as-quenched 500 HBW steels, Procedia Structural Integrity, Volume 42, 2022, Pages 871-878, ISSN 2452-3216,

Effect of prior austenite grain morphology on hydrogen embrittlement behaviour under plastic straining in as-quenched 500 HBW steels

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Author: Latypova, Renata1; Nyo, Tun Tun1; Seppälä, Oskari1;
Organizations: 1Materials and Mechanical Engineering, Centre for Advanced Steels Research, University of Oulu, Finland
2Department of Mechanical Engineering, School of Engineering, Aalto University, 02150 Espoo, Finland
3SSAB, 92100 Raahe, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.3 MB)
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Language: English
Published: Elsevier, 2022
Publish Date: 2023-01-04


Prior austenite grain (PAG) structure is an important factor influencing hydrogen embrittlement (HE) susceptibility of ultrahigh-strength steels. In this study, the effect of PAG shape and size on HE behaviour is investigated using a novel tuning-fork testing method and hydrogen thermal desorption spectroscopy (TDS). Different PAG structures were acquired via re-austenitization (860°C = A860, 960°C = A960) and rapid quenching of an as-received 500 HBW direct-quenched (DQ) steel, which has an auto-tempered lath-martensitic microstructure and elongated PAG morphology. Fractography reveals different crack propagation mechanisms depending on the PAG shape. With the elongated PAG structure, hydrogen-induced crack propagation transverse to elongated PAGs was transgranular quasi-cleavage. Propagation was partially intergranular with the equiaxed PAG structures, regardless of the PAG size, leading to equally faster fracture. The TDS results show that there are no significant differences between the total hydrogen contents, but re-austenitized A860 and A960 steels contain a higher fraction of weakly trapped hydrogen. This indicates that the PAG boundaries are not the dominant hydrogen traps, and the different crack propagation mechanisms are rather linked to the geometrical shape of the grain structure.

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Series: Procedia structural integrity
ISSN: 2452-3216
ISSN-E: 2452-3216
ISSN-L: 2452-3216
Volume: 42
Pages: 871 - 878
DOI: 10.1016/j.prostr.2022.12.110
Host publication: 23 European Conference on Fracture - ECF23
Host publication editor: Moreira, Pedro
dos Reis, Luis Filipe Galrao
Conference: European Conference on Fracture
Type of Publication: A4 Article in conference proceedings
Field of Science: 216 Materials engineering
Funding: This research was supported by Business Finland Oy and Academy of Finland (#337108).
Academy of Finland Grant Number: 337108
Detailed Information: 337108 (Academy of Finland Funding decision)
Copyright information: © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (