FEATURE ADVANCED MATERIALS & PROCESSES | MAY/JUNE 2024 49 History has shown that the development of cast alumina-forming alloys for this and other high temperature applications has been a challenge as evidenced by the lack of widespread availability of such products in the market—until now. The introduction of cost-effective AFA rolls, radiant burner tubes, and more recently, furnace tubes for ethylene cracking applications has resulted in a revolutionary change in the performance expectations and life expectation from these components. The 8-10× improvement in oxidation resistance in the heat-treat furnace environments is a technological breakthrough which has already demonstrated an ~80% increase in roll lives even with the short time of 5-6 years that these rolls have been in service. Decreased downtime due to eliminations of shutdowns for roll maintenance, improved product yield due to lack of surface defects, and improved productivity have the potential for long-term impacts on steel heat-treatment and processing technologies. Less frequent replacement of rolls will decrease investment in spares. The use of larger diameter rolls, along with better oxidation resistance that allows operation at higher temperatures, has enabled for the first time, the use of a more productive and efficient continuous mode of heat treatment for heavy gauge grades of alloy plate steels needed for applications in submarines, ships, and armored vehicles. These alloys are now available for use in other similar applications from Duraloy Technologies with the potential to have a very large impact on a variety of industrial, chemical/petrochemical processes and energy generation systems. For example, four TMA 6350 furnaces have been installed in domestic and international ethylene plants and have been operating successfully for over 21 months. It is anticipated that the use of these alloys in various high temperature applications will grow significantly in the next decade. ~HTPro Acknowledgments This research was sponsored by ARPA-E, U.S. Department of Energy. The authors would like to acknowledge Greg Cox, Dustin Heidel, Kevin O. Hansen for assistance with alloy fabrication, Christopher Stevens, Kelsey Epps, Charles Hawkins for mechanical property testing, Tom Geer, Victoria Cox, Tracie Lowe, M. Petrova for metallography, Mike Stephens for oxidation testing, and Doug Stringfield for specimen machining. This manuscript has been authored by UT-Battelle, LLC under Contract No. DEAC05-00OR22725 with the U.S. Department of Energy. The United States Government retains, and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/ downloads/doe-public-access-plan). For more information: Alex DeTrana, senior commercialization manager, Oak Ridge National Laboratory, detranaag@ornl.gov or Roman Pankiw, vice president, engineering and sales, Duraloy, techmgr@duraloy.com. References 1. Y. Yamamoto, et al., Development of Creep-Resistant, Alumina-Forming Ferrous Alloys for High-Temperature Structural Use, Proc. ASME ETAM2018, ETAM2018-6727, 2018. 2. G. Muralidharan, et al., Recent Developments in Cast Alumina-Forming Austenitic Stainless Steel Furnace Rolls, Proc. of the 2nd International Symposium on the Recent Developments in Plate Steels, p 513-520, 2018. 3. G. Muralidharan, et al., Development of Cast AluminaForming Austenitic Stainless Steels, JOM, First Online: September 6, 2016, doi.org/10.1007/s11837-016-2094-8. 4. M.P. Brady, et al., Development of 1100°C Capable Alumina-Forming Austenitic Alloys, Oxid Met, doi.org/ 10.1007/s11085-016-9667-3. 5. U.S. Patent 8,431,072, Cast Alumina Forming Austenitic Stainless Steels, G. Muralidharan, Y. Yamamoto, M. P. Brady, Issued April 30, 2013. Fig. 3 — A shipment of larger diameter furnace rolls manufactured for the newly commissioned furnace at ClevelandCliffs prior to installation. 12
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