University of Oulu

Sakari Pallaspuro, Teijo Limnell, Pasi Suikkanen, David Porter, T0 – T28J Correlation of Low-carbon Ultra-high-strength Quenched Steels, Procedia Materials Science, Volume 3, 2014, Pages 1032-1037, ISSN 2211-8128,

T₀ − T28J correlation of low-carbon ultra-high-strength quenched steels

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Author: Pallaspuro, Sakari1; Limnell, Teijo2; Suikkanen, Pasi2;
Organizations: 1University of Oulu, Centre for Advanced Steels Research, Materials Engineering Laboratory, P.O. Box 4200, 90014 Oulun yliopisto, Finland
2Ruukki Metals Oy, Rautaruukintie 155, P.O. Box 93, 92101 Raahe, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.3 MB)
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Language: English
Published: Elsevier, 2014
Publish Date: 2020-01-29


Direct-quenched structural steels are a cost-effective ultra-high-strength solution for demanding applications. These untempered, mainly S900 and S960 grade steels can possess good impact toughness and weldability when they contain low carbon contents and have low carbon equivalents. However, it is reported that as regards brittle fracture toughness these steels do not follow the commonly used correlation between the Charpy-V impact toughness transition temperature T28J and the fracture toughness reference temperature T₀, i.e. T₀ = T28J − 18 °C. These T₀ estimates are on the unconservative side, so there is a risk of overestimating the brittle fracture toughness of these steels in structural design when relying solely on impact toughness transition temperature values. In this study, the correlation between T₀ and T28J temperatures of low-carbon ultra-high-strength martensitic and martensitic-bainitic steels in the quenched state is analyzed. In total, 78 new and re-analyzed data sets are reported i.e. data for 39 steels tested in both longitudinal and transverse orientations. These data sets are then evaluated using the procedures found in the literature. A recently updated T₀ − T28J correlation is tested and it is shown that it gives less unconservative estimates of T0 by including the effects of yield strength and upper shelf energy. Finally a new correlation between T₀ and T28J for as-quenched low-carbon steels is proposed, i.e. T₀ = 0.8*T28J + 14 °C.

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Series: Procedia materials science
ISSN: 2211-8128
ISSN-E: 2211-8128
ISSN-L: 2211-8128
Volume: 3
Pages: 1032 - 1037
DOI: 10.1016/j.mspro.2014.06.168
Conference: European Conference on Fracture
Type of Publication: A4 Article in conference proceedings
Field of Science: 214 Mechanical engineering
216 Materials engineering
Funding: The financial support of the Finnish Funding Agency for Technology and Innovation (Tekes) is gratefully acknowledged, as is the support from the FIMECC DEMAPP programme of the Finnish Metals and Engineering Competence Cluster.
Copyright information: © 2014 Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (