Nondestructive detection of small internal defects in carbon steel by laser ultrasonics

Citation
T. Tanaka et Y. Izawa, Nondestructive detection of small internal defects in carbon steel by laser ultrasonics, JPN J A P 1, 40(3A), 2001, pp. 1477-1481
Citations number
9
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Volume
40
Issue
3A
Year of publication
2001
Pages
1477 - 1481
Database
ISI
SICI code
0021-4922(200103)40:3A<1477:NDOSID>2.0.ZU;2-4
Abstract
A small internal defect 100 mum in diameter in a carbon steel sample was su ccessfully detected by the laser ultrasonic technique. Irradiation of a Q-s witched Nd:YAG laser was used for ultrasonic generation, and a frequency-do ubled CW Nd:YAG laser combined with a Fabry-Perot etalon was used for detec tion of ultrasonic vibration on the carbon steel surface. The ratio of the internal defect diameter to the ultrasonic wavelength (d/lambda) was estima ted to be about 0.07. The dependence of the normalized amplitude of the def ect signal on the defect diameter was measured, and the ultrasonic reflecta nce by the cylindrical internal defect was roughly evaluated using the expe rimental results. It is considered that the laser ultrasonic technique has the ability to detect internal defects in industrial components and enginee ring structures, which is comparable to that of the conventional ultrasonic testing technique.