University of Oulu

Sakari Pallaspuro, Ann-Christin Hesse, Tim Engelke, Johannes Sainio, Sumit Ghosh, Vahid Javaheri, Klaus Dilger, Jukka Kömi, Impact toughness of an electron-beam welded 0.2C direct-quenched and partitioned steel, Procedia Structural Integrity, Volume 42, 2022, Pages 895-902, ISSN 2452-3216,

Impact toughness of an electron-beam welded 0.2C direct-quenched and partitioned steel

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Author: Pallaspuro, Sakari1; Hesse, Ann-Christin2; Engelke, Tim2;
Organizations: 1Materials and Mechanical Engineering, Centre for Advanced Steels Research, University of Oulu, Finland
2Institute of Joining and Welding, Technische Universität Braunschweig, Germany
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.9 MB)
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Language: English
Published: Elsevier, 2022
Publish Date: 2023-01-10


Third generation advanced high-strength steels, e.g., quenched and partitioned steels, are forthcoming structural materials, which consist of a martensitic matrix and a substantial proportion of stabilized residual austenite for improved deformability. A novel less energy-intensive processing route of direct-quenching and partitioning advances this concept by facilitating carbon partitioning to untransformed austenite directly from the quench-stop temperature. However, a major challenge also with these steels is how to maintain structural integrity in the welded end-products after additional heat-input reaching above a temperature where given microstructure is still stable. Heat-input limiting beam welding processes are a solution to this by minimizing degradation of the heat-affected zone (HAZ) and producing even-strength welded joints for S1100 and above. In this study, we report toughness properties of an electron-beam (EB) welded 0.2C-1.5Mn-0.5Si-0.8Al-1.1Cr-0.8Ni (wt.%) direct-quenched and partitioned steel (DQ&P) having a yield strength of ∼1100 MPa, and a direct-quenched (DQ) was used as a reference. Low-temperature post-weld heat treatment (PWHT) was considered, too. Weld seam, coarse-grained HAZ, and the base materials were tested for impact toughness. Both the DQ and DQ&P base materials have excellent impact toughness transition temperatures T28J below -100°C. The weld seam has very good low-temperature toughness already at this stage of optimisation with T28J of -66°C, which shows robustness of the chosen alloy. Increased residual austenite content increased upper shelf toughness but not T28J. Furthermore, both the DQ and DQP HAZs have T28J below -70°C, pointing to the weld seam as the weakest link. PWHT reduced low-temperature impact toughness in all the cases with T28J being above -40°C, clearly demanding reassessment of its feasibility.

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Series: Procedia structural integrity
ISSN: 2452-3216
ISSN-E: 2452-3216
ISSN-L: 2452-3216
Volume: 42
Pages: 895 - 902
DOI: 10.1016/j.prostr.2022.12.113
Host publication: Procedia Structural Integrity
Host publication editor: Moreira, Pedro
dos Reis, Luis Filipe Galrao
Type of Publication: A4 Article in conference proceedings
Field of Science: 216 Materials engineering
212 Civil and construction engineering
Funding: The authors wish to thank Business Finland for funding this research through the FOSSA program.
Copyright information: © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (