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- Bate, Pete, et al.
(författare)
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Application of laser-ultrasonics to texture measurements in metal processing
- 2017
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Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454 .- 1873-2453. ; 123, s. 329-336
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Tidskriftsartikel (refereegranskat)abstract
- The paper describes in principle how information about textures can be obtained through the application of laser-ultrasonics (LUS) which can be carried out at elevated temperatures, for example in connection with hot rolling. The benefits from getting a measure of texture in this way are explained together with the proposed methodology which is based on the elastic anisotropic properties of the textured material. Measurements are made using only a single laser pulse and in real-time. Two approaches are presented to modelling the propagation of elastic waves, ray tracing and finite difference modelling. These give consistent results but the latter provides a more complete prediction of the ultrasonic spectrum that can be quantitatively related to measured signals through a cross-correlation procedure. Some experimental results are presented for room temperature measurements on a sheet of interstitial-free steel. Agreement between experimental data and modelling results is good and allows estimation of the 4th order coefficients of the orientation distribution function.
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| 4. |
- Falkenström, Magnus, et al.
(författare)
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Laser ultrasonics for process control in the metal industry
- 2011
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Ingår i: Nondestructive Testing and Evaluation. - : Informa UK Limited. - 1058-9759 .- 1477-2671. ; 26, s. 237-252
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Forskningsöversikt (refereegranskat)abstract
- Laser ultrasonic (LUS) techniques show great promise for online measurement of material structures and properties during the processing of steels and other metals due to their high information content combined with their ability to operate in difficult environments. Laboratory-scale experiments are presented together with theoretical background showing how LUS can provide insight into the phenomena of recrystallisation, grain growth and phase transformation based on the measurements of velocities for different wave types and on their attenuation. This technique is unique in allowing dynamic observations of such phenomena at elevated temperatures. As microstructure is the most important factor governing the strength of metals, it follows that LUS signals are closely correlated with strength properties in many cases. The LUS equipment has been applied in several industrial trials to successfully evaluate mechanical properties of the product materials. It is also shown how absolute measurements of dimensions such as plate thickness can be made without physical contact and without the need for any calibration factors. © 2011 Taylor & Francis.
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| 5. |
- Hutchinson, Bevis, et al.
(författare)
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Anomalous ultrasonic attenuation in ferritic steels at elevated temperatures
- 2016
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Ingår i: Ultrasonics. - : Elsevier B.V.. - 0041-624X .- 1874-9968. ; 69, s. 268-272
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Tidskriftsartikel (refereegranskat)abstract
- An unexpected peak in attenuation has been observed at ∼800 °C when heating low carbon steels in a laser-ultrasonic instrument. An explanation is given in terms of enhanced crystalline anisotropy with increasing temperature in the bcc ferrite range combined with subsequent transformation to austenite at still higher temperatures. An analysis based on theoretical models of attenuation in the Rayleigh regime is in good agreement with the experimental observations.
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| 10. |
- Mauritzson, Lena, et al.
(författare)
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Texture studies using laser ultrasonics (LUS) in metal processing
- 2017
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The results and modelling analyses presented here showsthat laser-ultrasonics (LUS) provide a viable method for obtaining texture informationin metal sheets. LUSwhich can be carried out at elevated temperatures, and are suitablefor measurementsin connection withhot processing of steels and other metals. Two approaches are presented to modelling the propagation of elastic waves, ray tracing and finite difference modelling. These give consistent results but the latter provides a more complete prediction of the ultrasonic spectrum that can be quantitatively related to measured signals through a cross-correlation procedure.There is good reason to believe thatthis method enable in-line process controloftextures.
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