ISSN:
1662-8985
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The dependence of Charpy toughness on the microstructure and texture of two industrialgrades of API –X80 pipeline steel with a thickness of 15 and 17 mm, respectively, were studied inthis work. Standard size Charpy samples with a long axis orientated at 0, 22.5, 45, 67.5 and 90°with respect to the rolling direction of the plate were tested at different temperatures varying from-196°C to 20°C. Microstructure and texture of the plates were studied by means of electron backscatteringdiffraction (EBSD) and XRD. The highest value of the absorbed energy (440 J) wasmeasured at room temperature in the samples oriented with the long axis parallel to the rolling directionand the minimum values for the same temperature were observed in the samples enclosingan angle of 45° to RD (340J). Statistical model parameters obtained from Charpy impact tests werequantitatively correlated to microstructural parameters by means of a linear regression model withthe aim to describe the Brittle-Ductile Transition Curve in terms of microstructural features. Basedon dedicated experiments the Brittle Fracture Factor (BFF) parameter was introduced, which quantifiesthe fraction of the {100} planes oriented parallel to the crack propagation front. It was foundthat the Charpy toughness anisotropy of the plates in the lower shelf region can not be related onlyto their crystallographic texture, but to the microstructural anisotropy characterized by the grain sizevariations i.e. the density of grain boundaries in the different directions. Also the spatial distributionof the 2nd phase plays a determining role in the fracture behavior
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/39/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.15-17.840.pdf
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