Sources of acoustic emission during crack growth in ferritic steels

While laboratory applications of acoustic emission (AE) appear promising, industrial applications of AE techniques are hampered by background noise difficulties, problems of interpretation of monitoring system responses, and a general lack of emission from low-strength steels, which form the majority of industrial structures. The latter point is perhaps the most disturbing and presents the greatest obstacle to AE practitioners. It is hoped to provide an understanding of this problem by examining the source of AE in high-strength steels during a variety of cracking mechanisms and contrasting this behaviour with results obtained in a low-strength carbon–manganese steel.