University of Oulu

Renata Latypova, Oskari Seppälä, Tun Tun Nyo, Timo Kauppi, Sakari Pallaspuro, Saara Mehtonen, Hannu Hänninen, Jukka Kömi; Hydrogen-Induced Cracking of 500 HBW Steels Studied Using a Novel Tuning-Fork Test with Integrated Loadcell System. CORROSION 1 October 2020; 76 (10): 954–966. doi:

Hydrogen-induced cracking of 500 HBW steels studied using a novel tuning-fork test with integrated loadcell system

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Author: Latypova, Renata1; Seppälä, Oskari1; Nyo, Tun Tun1;
Organizations: 1Materials and Mechanical Engineering, Centre for Advanced Steels Research (CASR), University of Oulu, P.O. Box 4200, 90014 Oulu, Finland
2Arctic Steel and Mining RDI-group, Lapland University of Applied Science, 94600 Kemi, Finland
3SSAB, P.O. Box 93, 92101 Raahe, Finland
4Aalto University School of Engineering, Department of Mechanical Engineering, P.O. Box 14200, FI-00076 AALTO, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 1.9 MB)
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Language: English
Published: NACE International, 2020
Publish Date: 2021-01-01


Hydrogen embrittlement is a well-known problem with high-strength steels. An important aspect of hydrogen embrittlement research is the effect of the prior austenite grain (PAG) structure on hydrogen-induced fracture. The microstructural anisotropy of PAG structure depends on the steel manufacturing process. In this study, 500 HBW martensitic steels with different PAG structures are investigated with a novel tuning-fork test that utilizes an integrated loadcell system. The loadcell clamping system is used during hydrogen charging, allowing tracking of the applied force throughout the tests, which enables detection of separate phases of cracking and time-to-fracture. The elongated PAG morphology produces different results depending on the crack path direction in relation to the rolling direction, whereas the equiaxed PAG morphology does not manifest an orientation dependence. Depending on the PAG shape, also the fracture morphology differs. Time-to-fracture results show that elongated grain morphologies with transgranular quasi-cleavage crack propagation are more beneficial against hydrogen-induced fracture than equiaxed grain structure with intergranular crack propagation. These results demonstrate that the shape of the PAG structure plays an important role in the crack propagation mechanism and that it is important to consider the possible direction of hydrogen-induced cracks in the final structural applications.

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Series: Corrosion
ISSN: 0010-9312
ISSN-E: 1938-159X
ISSN-L: 0010-9312
Volume: 76
Issue: 10
Pages: 954 - 966
DOI: 10.5006/3592
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Funding: This research was supported by Business Finland Oy. Dr. Pallaspuro thanks the Academy of Finland (#311934) for funding.
Copyright information: © 2020, NACE International.