INFLUENCE OF AUSTENITIZING AND TEMPERING TEMPERATURE ON MICROSTRUCTURE, SUBSTRUCTURE AND MECHANICAL PROPERTIES OF CREEP RESISTANT 9CRNB STEEL

1 BEKEČ Pavel
Co-authors:
1,2 PARILÁK Ľudovít 1,2 BERAXA Pavol 3 FUJDA Martin 3 MATVIJA Miloš
Institutions:
1 ŽP Research and Development Centre, Ltd., Podbrezova, Slovakia, EU *bekec@zelpo.sk, parilak@zelpo.sk, beraxa.pavol@zelpo.sk
2 Faculty of Manufacturing Technologies with a Seat in Prešov, Prešov, Slovakia, EU
3 Faculty of Materials, Metallurgy and Recycling of the Technical University of Košice, Slovakia, EU, martin.fujda@tuke.sk, milos.matvija@tuke.sk
Conference:
28th International Conference on Metallurgy and Materials, Hotel Voronez I, Brno, Czech Republic, EU, May 22nd - 24th 2019
Proceedings:
Proceedings 28th International Conference on Metallurgy and Materials
Pages:
581-586
ISBN:
978-80-87294-92-5
ISSN:
2694-9296
Published:
4th November 2019
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
38 views / 13 downloads
Abstract

This paper deals with influence of austenitizing and tempering temperature on microstructure, substructure and mechanical properties of creep resistant 9CrNB steel. Austenitizing temperature of 1050 °C was used with holding time of 15 min (state N1) and 45 min (state N3). Subsequently, the samples in these conditions were tempered at 790 °C/60 min (state S1 and S3). Microstructure after austenitization is formed by lath martensite and low bainite. The microstructure after tempering was formed by tempered martensite and lower bainite, with darker and lighter areas. This is due to the non-homogeneous distribution of precipitates. It can also be seen, that fine particles of precipitates were found at the martensite and low bainite lattice interfaces. It is likely to be a carbide particles, whereby excluded this particles occurred during the tempering on the original grain boundaries of austenite. The substructure was analysed in the following austenitizing conditions: 1050 °C/15 min and 1050 °C/45 min and their subsequent tempering at 790 °C/60 min. The precipitates were identified by selective electron diffraction analysis. The mechanical properties were evaluated after austenitization and tempering conditions.

Keywords: creep resistant steel, martensitic microstructure, tempering temperature, 9Cr steel, boron, grain boundary
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