High temperature strengths and steam oxidation properties of new 9--12%Cr ferritic steel pipes for USC boilers
- Babcock-Hitachi K.K., Hiroshima (Japan)
An important factor in the development of ultra super critical (USC) boilers is the selection of materials for thick-walled components such as superheater headers and main steam pipes. High temperature strengths and steam oxidation properties were examined for newly developed steels NF616(9Cr0.5Mo1.8WNbV) and HCM12A(11Cr0.4Mo2W1CuNbV). In the weldments of these steels, the heat affected zone(HAZ) near the parent metal was softened by welding heat cycles. This HAZ softening had caused reduction in creep rupture strength when tested in uniaxial mode. To assess the influence of HAZ softening on the creep strengths of actual components, internal pressure creep tests were conducted using HCM12A hollow specimens with circumferential or longitudinal welds. The results indicated a possibility that uniaxial creep rupture tests could give conservative results and the HAZ softening would not become a critical problem in actual components. Concerning steam oxidation properties, the effect of Si content in NF616 was examined and a proper range of Si under USC steam conditions was proposed. These steels are expected to be applied for high temperature components in future USC power plants under steam conditions of 29.4MPa/625 C or possibly higher.
- OSTI ID:
- 233913
- Report Number(s):
- CONF-950908-; ISBN 0-87170-539-7; TRN: IM9624%%31
- Resource Relation:
- Conference: 2. international conference on heat resistant materials, Gatlinburg, TN (United States), 11-14 Sep 1995; Other Information: PBD: 1995; Related Information: Is Part Of Heat-resistant materials 2. Conference proceedings of the 2. international conference on heat-resistant materials; Natesan, K. [ed.] [Argonne National Lab., IL (United States)]; Ganesan, P. [ed.] [INCO Alloys International, Inc., Huntington, WV (United States)]; Lai, G.Y. [ed.] [Haynes International, Inc., Kokomo, IN (United States)]; PB: 687 p.
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
20 FOSSIL-FUELED POWER PLANTS
IRON BASE ALLOYS
WELDED JOINTS
OXIDATION
CHROMIUM ALLOYS
TUNGSTEN ALLOYS
COPPER ALLOYS
MICROSTRUCTURE
MECHANICAL PROPERTIES
FOSSIL-FUEL POWER PLANTS
BOILERS
MOLYBDENUM ADDITIONS
NIOBIUM ADDITIONS
VANADIUM ADDITIONS
CHEMICAL COMPOSITION
HEAT AFFECTED ZONE
HARDNESS
TENSILE PROPERTIES
CREEP
STEAM
SCALING
EXPERIMENTAL DATA