Creep strength of high-Cr ferritic steels designed using neural networks and phase stability calculations

F. Masuyama and H. K. D. H. Bhadeshia


The highest creep rupture strength of recent 9-12%Cr steels which have seen practical applications is about 130 MPa at 600°C and 100,000 h. While the 630°C goal may be realized, much more work is needed to achieve steam temperatures up to 650°C. Conventional alloy development techniques can be slow and it is possible that mathematical models can define the most economical path forward, perhaps leading to novel ideas. A combination of mechanical property models based on neural networks, and phase stability calculations relying on thermodynamics, has been used to propose new alloys, and the predictions from this work were published some time ago. In the present work we demonstrate how the proposed alloys have performed in practice, considering long term creep data and microstructural observations. Comparisons are also made with existing enhanced ferritic steels such as Grade 92 and other advanced 9-12%Cr steels recently reported.

Fifth Int. Conf. on Advances in Materials Technology for Fossil Power Plants October 3-5 (2007) 4B-01. Published by EPRI, Palo Alto, California, USA


Superalloys Titanium Bainite Martensite Widmanstätten ferrite
Cast iron Welding Allotriomorphic ferrite Movies Slides
Neural Networks Creep Mechanicallly Alloyed Theses Retained Austenite

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