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Characterisation of the microstructural evolution of aged super 304H (UNS30432) advanced austenitic stainless steel

conference contribution
posted on 18.07.2019, 10:26 by Charlotte PulsfordCharlotte Pulsford, Mark JepsonMark Jepson, Rachel ThomsonRachel Thomson, Tapasvi Lolla, John A. Siefert
Advanced austenitic stainless steels, such as Super 304H, have been used in reheater and superheater tubes in supercritical and ultra-supercritical power plants for many years now. It is important to characterise the microstructure of ex-service reheater and superheater tubes as this will help to understand long-term microstructural evolution and degradation of the material which can impact the performance and lifetime of the components that are in service. In this research, the microstructure of an ex-service Super 304H reheater tube that has been in service for 99,000 hours at an approximate metal temperature of 873K (600°C), has been characterised. The characterisation techniques used were electron microscopy based and include imaging and chemical analysis techniques. Seven phases were observed as a result of the characterisation work. The phases observed were, MX carbo-nitrides rich in niobium, copper rich particles, M23C6, sigma, Z phase, a cored phase and a BCC phase.

Funding

The authors would like to acknowledge the Engineering and Physical Research Council (EPSRC) and the Centre for Carbon Capture and Storage and Cleaner Fossil Energy (EP/L016362/1) for their support on this project.

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Materials

Published in

Joint EPRI-123HiMAT International Conference on Advances in High Temperature Materials

Citation

PULSFORD, C. ... et al., 2019. Characterisation of the microstructural evolution of aged super 304H (UNS30432) advanced austenitic stainless steel. Presented at the Joint EPRI-123HiMAT International Conference on Advances in High Temperature Materials, Nagasaki, Japan, 21-25th October.

Publisher

© Electric Power Research Institute (EPRI)

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Acceptance date

12/07/2019

Publication date

2019

Notes

This paper is in closed access.

Language

en

Location

Nagasaki, Japan

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