Jepson_Manuscript (revised submission).pdf (9.57 MB)
Investigation of microstructural evolution and creep rupture behaviour of 9% Cr MarBN steel welds
journal contribution
posted on 2020-06-08, 08:18 authored by X Xu, A Benaarbia, D Allen, Mark JepsonMark Jepson, W SunThe weldments made from the 9-12% Cr tempered martensitic steel are associated with a complex microstructure arising from complicated thermal histories of the fusion and heat affected zones. The complicated microstructural and micro-mechanical states in these critical regions provide a challenge for the determination of creep failure mechanisms. Based on detailed metallographic examination, the microstructural distribution in the heat affected zone of the welds constructed using a recently developed 9% Cr MarBN steel, IBN-1, has been identified and classified into Equiaxed Zone (EZ), Duplex Zone (DZ) and Over-tempered Zone (OZ). Cross-weld testing performed at 650°C has revealed a significant reduction in creep life as compared to bulk material. Creep rupture has been shown to occur in the parent metal region with a ductile manner at a high stress, whereas creep rupture initiates in the DZ region in an intergranular manner at a low stress. Detailed metallographic investigation has further revealed a higher damage susceptibility in the regions along the pre-existing Prior Austenite Grain Boundaries (PAGBs). The diffusional reaustenitisation of local microstructure along the PAGBs leads to a lower strength of matrix in combination with a lack of intergranular precipitates as compared to the surrounding microstructure formed after displacive reaustenitisation
Funding
(EPSRC) Advanced Industrial Manufacture of Next-Generation MARBN Steel for Cleaner Fossil Plant : EP/N509942/1
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Materials
Published in
Materials Science and Engineering: AVolume
791Publisher
Elsevier BVVersion
- AM (Accepted Manuscript)
Rights holder
© ElsevierPublisher statement
This paper was accepted for publication in the journal Materials Science and Engineering: A and the definitive published version is available at https://doi.org/10.1016/j.msea.2020.139546Acceptance date
2020-05-09Publication date
2020-05-18Copyright date
2020ISSN
0921-5093Publisher version
Language
- en