Accession Number:

ADA058887

Title:

On the Amplitude Distribution of Burst Emission due to MnS Inclusions in HSLA Steels.

Descriptive Note:

Technical rept.,

Corporate Author:

CALIFORNIA UNIV LOS ANGELES DEPT OF MATERIALS

Personal Author(s):

Report Date:

1978-07-01

Pagination or Media Count:

15.0

Abstract:

It is well known that the ductility of a steel plate, particularly in the thickness short transverse direction, is sensitive to the number, size, shape and distribution of nonmetallic primarily MnS inclusions. In this study, acoustic emission behavior was correlated to several inclusion parameters, varied by rolling mill practices and different sulphur levels in the steel used. Burst-type acoustic emission signals were observed in the thickness direction samples. Their numbers and intensity increased with the sulphur content, and also depended on the rolling ratio and finish rolling temperature. The origin of burst emission was established as the decohesion of flattened MnS inclusions. Amplitude distribution of acoustic emission signals was describable by a Weibull distribution. It was also found that the size distribution of MnS inclusions takes an identical form. The two independently determined distributions were correlated by considering the stored elastic strain energy at an inclusion and of the transducer response to mechanical pulse excitation. To explain stress dependence of Acoustic Emission amplitude distribution, the size dependence of decohesion probability was also introduced. Author

Subject Categories:

  • Metallurgy and Metallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE