Optimised microstructure for increased creep rupture strength of MarBN steels. (May 2015)

• Record Type: Journal Article
• Authors: Plesiutschnig, E.; Beal, C.; Paul, S.; Zeiler, G.; Sommitsch, C.
• Is Part Of: Materials at high temperatures. Volume 32:Number 3(2015)
• Page Start: 318
• Page End: 322
• Publication Date: 2015-05
• Subjects: MarBN steels, -- Creep, -- SEM, -- EBSD, -- Steam turbine, -- Hot pipes; Materials at high temperatures -- Periodicals; High temperatures -- Periodicals; 620.1121705
• DOI: 10.1179/0960340914Z.00000000073
• Languages: English
• ISSNs: 0960-3409

Abstract

Abstract : The efficiency of modern steam power plants relies heavily on the inlet fluid temperature and pressure. Thus it is necessary to improve the materials of cast, rolled and forged parts such as case, pipes and rotor. Two chemical compositions of 9%Cr creep resistant steels were investigated. Different heat treatments were applied to modify the prior austenite grain size (to diameters of 50, 100, 300 and 700 μm) and to modify the substructure. The microstructure changes were further investigated by LOM, SEM and EBSD. Then, these different microstructures were exposed to the uniaxial creep rupture test at 650°C and 150 MPa. Comparative results reveal the influence of the modified microstructure on creep rupture time, ductility and fracture.