The microstructure effect on the fracture toughness of ferritic Ni-alloyed steels
| Autor: | Adriano Scheid, Douglas Martinazzi, Carlos Eduardo Fortis Kwietniewski, Tiago Renck, Lorenzo Marzari Félix |
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| Rok vydání: | 2016 |
| Předmět: |
Quenching
0209 industrial biotechnology Toughness Materials science Mechanical Engineering Metallurgy Crack tip opening displacement 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics Microstructure Grain size 020901 industrial engineering & automation Fracture toughness Mechanics of Materials General Materials Science Grain boundary Tempering Composite material 0210 nano-technology |
| Zdroj: | Materials Science and Engineering: A. 661:96-104 |
| ISSN: | 0921-5093 |
| Popis: | Production of oil and gas in the Brazilian pre-salt faces several technical challenges and one of them that is a major concern is the presence of CO 2 in high concentration. The aim of this work is to evaluate the fracture toughness of two nickel-containing steels as an alternative material to manufacture low-temperature toughness improved CO 2 transporting pipelines for Enhanced oil recovery (EOR). Optical and scanning electron microscopies were employed to characterize the steels microstructures. Electron back-scattered diffraction was used to estimate the effective grain size and the density of high-angle grain boundaries. Fracture toughness was determined by the use of the crack tip opening displacement methodology. The results indicated that for the as-rolled condition the large islands of the microconstituent M/A in the 5 1/2 Ni steel had a detrimental effect on fracture toughness at −100 °C, while finer M/A particles and lower effective grain size with higher density of high-angle grain boundaries in the 9 Ni steel turned its fracture toughness practically temperature independent. Additionally, heat treatment (quenching and tempering) has the potential to dissolve the M/A hard particles and consequently improve fracture toughness at low temperature. |
| Databáze: | OpenAIRE |
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