Title: Development and microstructure of advanced creep resistant ferritic steels

Authors: Jaroslav Koukal, Martin Sondel, Drahomir Schwarz, Vaclav Foldyna

Addresses: Areal VSB-TU Ostrava, 17. listopadu 2172/15, 708 33 Ostrava – Poruba, Czech Republic. ' Areal VSB-TU Ostrava, 17. listopadu 2172/15, 708 33 Ostrava – Poruba, Czech Republic. ' Areal VSB-TU Ostrava, 17. listopadu 2172/15, 708 33 Ostrava – Poruba, Czech Republic. ' Areal VSB-TU Ostrava, 17. listopadu 2172/15, 708 33 Ostrava – Poruba, Czech Republic

Abstract: During the past two decades, a new generation of creep resistant ferritic steels has been developed for boiler and turbine component applications in advanced power generation plants operating with inlet steam temperature in the range 600 to 650°C. It is generally accepted that development of new steels with higher creep resistance must be based on detail knowledge of strengthening and degradation processes and structural stability. The aim of the present paper is to point out the most significant strengthening and degradation processes during creep exposure of ferritic steels with respect to chemical composition and structural changes occurring during creep at elevated temperatures. The attention will be devoted to low alloy steels with Cr content up to three mass % and modified chromium steels containing nine to 12 mass % Cr.

Keywords: advanced steels; creep resistant steels; ferritic steels; precipitation strengthening; solid solution strengthening; interparticle spacing; creep rupture strength; weld joints; heat affected zone; HAZ; microstructure; boiler components; turbine components; power generation plants; chemical composition; structural changes; low alloy steels; chromium steels.

DOI: 10.1504/IJMMP.2011.040441

International Journal of Microstructure and Materials Properties, 2011 Vol.6 No.1/2, pp.122 - 131

Published online: 27 May 2011 *

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