The effect of the cooling rate T from austenitic field on the microstructural evolution and the mechanical stability of MANET steel for increasing times of tempering at 700 degrees C has been studied by means of Charpy tests, SEM observations with EDS microanalysis and X-ray diffraction analysis. The investigated rates T range from 150 to 3600 degrees C/min. The ductile to brittle transition temperature, the upper shelf energy and the slope a Delta E/Delta T in the transition region depend on the time of treatment with variations more pronounced in samples slowly cooled. After tempering times of about 20 h at 700 degrees C the samples cooled with T = 150 degrees C/min show a mixed mode of brittle fracture (quasi-cleavage and intercrystalline) with good correspondence between Cr-enriched zones and surfaces fractured in intercrystalline mode. Only quasi-cleavage mechanism is operative in samples quenched with T = 3600 degrees C/min, which present fracture surfaces with uniform Cr distribution. The results are discussed on the basis of C-Cr associate distributions determined by internal friction tests.

Gondi, P., Montanari, R., Sili, A., Tata, M.e. (1996). Effects of thermal treatments on the ductile to brittle transition of MANET steel. In Journal of Nuclear Materials (pp.248-252). AMSTERDAM : ELSEVIER SCIENCE BV [10.1016/0022-3115(95)00176-X].

Effects of thermal treatments on the ductile to brittle transition of MANET steel

GONDI, PRIMO;MONTANARI, ROBERTO;TATA, MARIA ELISA
1996-01-01

Abstract

The effect of the cooling rate T from austenitic field on the microstructural evolution and the mechanical stability of MANET steel for increasing times of tempering at 700 degrees C has been studied by means of Charpy tests, SEM observations with EDS microanalysis and X-ray diffraction analysis. The investigated rates T range from 150 to 3600 degrees C/min. The ductile to brittle transition temperature, the upper shelf energy and the slope a Delta E/Delta T in the transition region depend on the time of treatment with variations more pronounced in samples slowly cooled. After tempering times of about 20 h at 700 degrees C the samples cooled with T = 150 degrees C/min show a mixed mode of brittle fracture (quasi-cleavage and intercrystalline) with good correspondence between Cr-enriched zones and surfaces fractured in intercrystalline mode. Only quasi-cleavage mechanism is operative in samples quenched with T = 3600 degrees C/min, which present fracture surfaces with uniform Cr distribution. The results are discussed on the basis of C-Cr associate distributions determined by internal friction tests.
7th International Conference on Fusion Reactor Materials (ICFRM-7)
OBNINSK, RUSSIA
SEP 25-29, 1995
Rilevanza internazionale
contributo
1996
Settore ING-IND/21 - METALLURGIA
English
Austenite; Brittleness; Cooling; Ductility; Fracture; Heat treatment; Martensite; Stability; Tempering; Martensitic steels; Stainless steel
Intervento a convegno
Gondi, P., Montanari, R., Sili, A., Tata, M.e. (1996). Effects of thermal treatments on the ductile to brittle transition of MANET steel. In Journal of Nuclear Materials (pp.248-252). AMSTERDAM : ELSEVIER SCIENCE BV [10.1016/0022-3115(95)00176-X].
Gondi, P; Montanari, R; Sili, A; Tata, Me
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/51745
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