Papaelias, Mayorkinos PH. (2004). Detection and measurement of phase transformation in steel using electromagnetic sensors. University of Birmingham. Ph.D.
|
Papaelias2004PhD.pdf
Text - Accepted Version Available under License All rights reserved. Download (28MB) | Preview |
Abstract
Modem strip steel production requires accurate control of the cooling process at the run out table in order to achieve the desired microstructure and hence mechanical properties. Optical pyrometers are currently used by the steel industry to monitor temperature, and hence infer microstructure, however, their performance is imperfect due to the harsh environment that exists within the run out table. Methods for measuring micro structure directly on a strip steel run-out table are the subject of investigation. The present thesis is concerned with the assessment of an electromagnetic (EM) sensor capable of detecting the formation of ferromagnetic ferrite from paramagnetic austenite below the Curie temperature. From the results obtained it was found that the EM sensor can successfully detect the formation of ferrite below the Curie temperature but that the signal (i.e. impedance) can be significantly affected by the formation of a decarburised ferrite layer around the samples. It was also revealed that the impedance value is monotonically (nonlinear) related to the ferrite volume fraction and depends on the morphology / distribution of the ferromagnetic phase and hence is influenced by the prior austenite grain size. Results from finite element (FE) simulations designed to enable prediction of the impedance value from the microstructure are also presented showing that two dimensional FE simulations can be successfully used to model the experimental trends observed. The combination of modelling and measurement has shown that EM sensors can be used to directly monitor the ferrite transformation (below the Curie temperature) thus providing a measure of ferrite volume fraction and also a means of identifying ferrite distribution in the microstructure. Based on the conclusions drawn from the present thesis the development of an EM sensor that measures microstructure during transformation in an industrial hot rolling mill is a realistic possibility.
| Type of Work: | Thesis (Doctorates > Ph.D.) |
|---|---|
| Award Type: | Doctorates > Ph.D. |
| Licence: | All rights reserved |
| College/Faculty: | Schools (1998 to 2008) > School of Engineering |
| School or Department: | Department of Metallurgy and Materials |
| Funders: | Engineering and Physical Sciences Research Council, Other |
| Other Funders: | Corus Group U.K. |
| Subjects: | T Technology > TA Engineering (General). Civil engineering (General) |
| URI: | http://etheses.bham.ac.uk/id/eprint/14025 |
Actions
 |
Request a Correction |
 |
View Item |
Downloads
Downloads per month over past year