Examinando por Autor "Mayr, Peter"

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Anomalous steam oxidation behavior of a creep resistant martensitic 9 wt. % Cr steel
(Elsevier, 2013-06-09) Agüero, Alina; González, Vanessa; Mayr, Peter; Spiradek Hahn, Krystina; Ministerio de Economía y Competitividad (MINECO)
The efficiency of thermal power plants is currently limited by the long-term creep strength and the steam oxidation resistance of the commercially available ferritic/martensitic steel grades. Higher operating pressures and temperatures are essential to increase efficiency but impose important requirements on the materials, from both the mechanical and chemical stability perspective. It has been shown that in general, a Cr wt. % higher than 9 is required for acceptable oxidation rates at 650 °C, but on the other hand such high Cr content is detrimental to the creep strength. Surprisingly, preliminary studies of an experimental 9 wt. % Cr martensitic steel, exhibited very low oxidation rates under flowing steam at 650 °C for exposure times exceeding 20,000 h. A metallographic investigation at different time intervals has been carried out. Moreover, scanning transmission electron microscopy (STEM) analysis of a ground sample exposed to steam for 10,000 h at 650 °C revealed the formation of a complex tri-layered protective oxide comprising a top and bottom Fe and Cr rich spinel layer with a magnetite intermediate layer on top of a very fine grained zone.
Acceso Abierto
Co-ordination of European Research in Structural Materials for Power Generation Equipment
(University of Liège, 2014-09-17) Sommitsch, Chrisof; Vanstone, Rod; Kern, Torsten Ulf; Barnard, Peter; Mayr, Peter; Thompson, Rachel; Agüero, Alina
Sommitsch, C., Vanstone, R., Kern, T.-U., Barnard, P., Mayr, P., Thomson, R., & Agüero, A. (2014). Co-ordination of European Research in Structural Materials for Power Generation Equipment. In Liège Conference on Materials for Advanced Power Engineering (Vol. Band / Volume 234, pp. 3-18). (Schriften des Forschungszentrums Jülich, Reihe Energie & Umwelt / Energy & Environment). ..
Acceso Abierto
Experience with 9Cr3W3CoVNbBN base material and crosswelds at 650°C for implementation in USC power plants
(National Institute for Materials Science, Tsukuba , Japan, 2009-06-14) Mayr, Peter; Mendez Martín, Francisca; Holzer, Iván; Agüero, Alina; González, Vanessa; Baumgartner, Susanne; Cerjak, Horst Hannes
This manuscript gives an overview on recent developments of a martensitic steel grade based on 9Cr3W3CoVNb with controlled additions of boron and nitrogen. Alloy design by thermodynamic equilibrium calculations and calculation of boron-nitrogen solubility is discussed. Two melts of a 9Cr3W3CoVNb steel were produced. The oxidation resistance was examined at 650°C in steam atmosphere. The alloy exhibited high resistance to steam oxidation at 650°C for at least 5.000 hours of exposure. Microstructural evolution during welding within the heat-affected zone was investigated by physical weld simulation, thermo-dilatometry and in situ X-ray diffraction using high energy synchrotron radiation. The heat-affected zone microstructure is characterized by optical microscopy. Two multilayer welds, one with a nickel based filler and one with a newly developed flux cored filler of matching chemical composition, were fabricated. All weldability experiments showed that within the heat-affected zone the initial base material microstructure is retained to a large extent. The formation of a uniform fine-grained heat-affected zone region is suppressed. Uniaxial creep tests of base material, weld metal and crossweld specimens were started at different levels of stress at 650°C. Up to the established maximum testing time of 20.000 hours, the base material shows significant improvement compared to standard 9 wt. % Cr grades P91 and P92. Crossweld specimens show an improved strength level, higher than that of grade P92 base material. Preliminary results of an extensive testing program on a 9Cr3W3CoVNbBN steel show significant improvement compared to the state-of-the-art 9 wt. % Cr martensitic steel grades.
Acceso Abierto
Improved Creep and Oxidation Behavior of a Martensitic 9Cr Steel by the Controlled Addition of Boron and Nitrogen
(University of Liege, 2010-09-27) Mayr, Peter; Holzer, Iván; Mendez Martín, Francisca; Albu, Mihaela; Mitsche, Stefan; González, Vanessa; Agüero, Alina
Acceso Abierto
Steam oxidation behavior of high strength newly developed ferritic/martensitic steels at 650º C
(2010-05-24) Agüero, Alina; González, Vanessa; Mayr, Peter; Spiradek, Krystina