Keränen, L., Nousiainen, O., Javaheri, V., Kaijalainen, A., Pokka, A.-P., Keskitalo, M., Niskanen, J., & Kurvinen, E. (2022). Mechanical properties of welded ultrahigh-strength S960 steel at low and elevated temperatures. Journal of Constructional Steel Research, 198, 107517. https://doi.org/10.1016/j.jcsr.2022.107517
Mechanical properties of welded ultrahigh-strength S960 steel at low and elevated temperatures
|Author:||Keränen, Lassi1; Nousiainen, Olli1; Javaheri, Vahid1;|
1Materials and Mechanical Engineering, University of Oulu, Finland
2Kerttu Saalasti Institute, Future Manufacturing Technologies (FMT), University of Oulu, Finland
|Online Access:||PDF Full Text (PDF, 6.2 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2022090657631
|Publish Date:|| 2022-09-06
New ultrahigh-strength steels have been developed to meet the need for better performance, load bearing capacity, safety and weight saving. However, the design guidelines are incomplete, especially regarding the design of welded ultrahigh-strength steel components in fluctuating operating conditions. This reduces usability and can cause serious safety risks when the welded structures are in use. The heat input and cooling rate have a significant effect on the microstructure and mechanical properties of the ultrahigh-strength steels. Therefore, a model to predict the strength and microstructure, based on welding parameters, is required for designers to create safer solutions in engineering design. In this study, a 6 mm thick S960 low alloy ultrahigh-strength steel was welded using gas metal arc welding (MAG) and laser welding. The effects of welding heat input and operating temperature on the tensile properties, hardness, microstructure, and fracture mechanism of the welded specimens were investigated. The effects of operating temperature on the mechanical properties of welded joints were investigated by performing tensile tests between temperatures of −80 °C and + 400 °C. The unwelded base material was also tested in the same temperature range. The results showed a ductile fracture mechanism in all the samples regardless of the test temperature and welding heat input. However, the tensile strengths and elongations increased when the test temperature drops to −80 °C from room temperature. In addition, mathematical predictions for the strength and elongation properties, and grain sizes in heat-affected zones, as a function of temperature and welding heat input were proposed.
Journal of constructional steel research
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
216 Materials engineering
212 Civil and construction engineering
The authors are grateful for financial support from Business Finland for the FOSSA project (Dno 5397/31/2021). The Tauno Tönning Foundation is also acknowledged for their financial support to the corresponding author. The authors are also grateful to the Machine shop of the University of Oulu and the laboratory staff of the Materials and Mechanical Engineering research unit for help with mechanical testing and specimen preparation. Finally, the authors are grateful for the test materials from SSAB Europe in Finland.
© 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).