This paper is an overview of effect of micro-structure on ultrasonic transparency. It aims in verifying the capabilities of nondestructive evaluation (NDE) of special carbon steel which applied after quenching and tempering and designated to the production of disk for gas turbine through ultrasonic transparency (UT) testing. UT tests were carried out on several samples made of this special carbon steel. There is a brief discussion which is supported by the experiment, how heat treatment definitely can affect the ultrasonic attenuation. Since grain size distribution, carbon content, and normalizing temperature have a general effect on micro-structure which will directly leads to ultrasonic attenuation; there study also included under this paper. The conclusion is that while heat treatment does not typically affect the velocity of acoustic waves, it directly can affect the ultrasonic transparency. This study gives a solid correlation between ultrasonic transparency results and micro-structure in which it is confirmed that “As the grain dimension decreases the UT result also decreases and vice versa”.
In questo lavoro di tesi viene fornita una panoramica dell'effetto della microstruttura sulla trasparenza ad ultrasuoni. Essa mira a verificare le capacità di valutazione non distruttiva di un acciaio speciale al carbonio, applicato dopo tempra e rinvenimento e designato per la produzione di dischi per turbina a gas, tramite test di trasparenza ad ultrasuoni (UT). Prove agli ultrasuoni sono state effettuate su campioni caratterizzati da diversi trattamenti termici. Lo studio tende a valutare l'effetto della dimensione dela grano e della temperatura di trattamento termico sull'attenuazione delle onde ultrasonore. In conclusione si può affermare che il trattamento termico non influisce in genere sulla velocità di propagazione delle onde acustiche, ma può influenzare la trasparenza ad ultrasuoni. Questo studio dà una solida correlazione tra i risultati di trasparenza ad ultrasuoni e microstruttura in cui viene confermato che un un indice del grano maggiore corrisponde ad una migliore trasparenza del materiale e viceversa.
Ultrasound transparency of special carbon steel as function of microstructure features
MOHAMMED, BINIYAM JEMAL
2011/2012
Abstract
This paper is an overview of effect of micro-structure on ultrasonic transparency. It aims in verifying the capabilities of nondestructive evaluation (NDE) of special carbon steel which applied after quenching and tempering and designated to the production of disk for gas turbine through ultrasonic transparency (UT) testing. UT tests were carried out on several samples made of this special carbon steel. There is a brief discussion which is supported by the experiment, how heat treatment definitely can affect the ultrasonic attenuation. Since grain size distribution, carbon content, and normalizing temperature have a general effect on micro-structure which will directly leads to ultrasonic attenuation; there study also included under this paper. The conclusion is that while heat treatment does not typically affect the velocity of acoustic waves, it directly can affect the ultrasonic transparency. This study gives a solid correlation between ultrasonic transparency results and micro-structure in which it is confirmed that “As the grain dimension decreases the UT result also decreases and vice versa”.File | Dimensione | Formato | |
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https://hdl.handle.net/10589/72370