NOVEL CONCEPT FOR DIRECT-QUENCHED ULTRAHIGH-STRENGTH STEEL

1 KAIJALAINEN Antti
Co-authors:
1 SAASTAMOINEN Ari 1 HANNULA Jaakko 1 HEIKKALA Jouko 2 KESTI Vili 2 SUIKKANEN Pasi 1 PORTER David 1 KÖMI Jukka
Institutions:
1 Materials and Production Engineering – University of Oulu, Oulu, Finland, EU
2 SSAB Europe Oy, Raahe, Finland, EU
Conference:
26th International Conference on Metallurgy and Materials, Hotel Voronez I, Brno, Czech Republic, EU, May 24th - 26th 2017
Proceedings:
Proceedings 26th International Conference on Metallurgy and Materials
Pages:
635-641
ISBN:
978-80-87294-79-6
ISSN:
2694-9296
Published:
9th January 2018
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
20 views / 10 downloads
Abstract

In the present study, direct-quenched steel with and without tempering at 600 °C has been studied in order to evaluate the possibilities of widening the range of strengths that can be produced from a single base composition. Microstructural studies of direct-quenched (DQ) and direct-quenched and tempered (DQT) steels showed that, in both cases, the microstructure consisted of mainly bainite formed from highly pancaked prior austenite grains, the main difference being a larger carbide size in the tempered condition. The results show that steels with minimum specified yield stresses of 900 and 960 MPa with good impact toughness and bendability properties can be produced from a single composition by employing respectively DQ and DQT processing. After tempering impact toughness and bendability was even better.

Keywords: bainite, bendability, direct quenching, ductility, tempering
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