Use of electromagnetic acoustic resonance method to detect micro-voids viaevaluation of ultrasonic wave attenuation coefficient of SUS304 steel fabricated by hot isostatic press

Citation
H. Nishida et al., Use of electromagnetic acoustic resonance method to detect micro-voids viaevaluation of ultrasonic wave attenuation coefficient of SUS304 steel fabricated by hot isostatic press, JSME A, 44(1), 2001, pp. 8-16
Citations number
17
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Mechanical Engineering
Journal title
JSME INTERNATIONAL JOURNAL SERIES A-SOLID MECHANICS AND MATERIAL ENGINEERING
ISSN journal
1344-7912 → ACNP
Volume
44
Issue
1
Year of publication
2001
Pages
8 - 16
Database
ISI
SICI code
1344-7912(200101)44:1<8:UOEARM>2.0.ZU;2-S
Abstract
Creep damage in SUS304 steel samples fabricated by a hot isostatic press (H IP) at 1 050 degreesC was evaluated using the electromagnetic acoustic reso nance (EMAR), noise energy and ultrasonic spectroscopy (first moment) metho ds. The coefficients of attenuation of 1.1 to 5.4 MHz electromagnetically e xcited acoustic waves in the samples were investigated. By reducing diffrac tion loss and the loss to the electromagnetic acoustic transducer due to tr ansmission of the ultrasonic waves via mechanical contacts, it was possible to detect shear wave attenuation coefficients as low as 2.5 x 10(-4)/micro second at 1.1 MHz. With specimens fabricated at pressure of 170 MPa, the at tenuation coefficient increased in proportion to frequency up to 5.4 MHz, w hereas with specimens fabricated at pressure lower than 80 MPa the attenuat ion coefficient increased rapidly above 4 MHz. The void fraction was found to be greater in specimens fabricated under lower pressure, which may be re sponsible for the markedly higher ultrasonic attenuation in the specimens f abricated at pressure lower than 80 MPa. It was apparent from the experimen ts that the EMAR method detects creep voids with greater sensitivity than t he other methods. Accordingly we hope it will be possible for the EMAR meth od to be used on real facilities in the future.