ACOUSTIC-EMISSION CHARACTERIZATION OF A MEDIUM STRENGTH STEEL DURING HYDROGEN PERMEATION PROCESSES

Abstract

The characteristics of acoustic emission (AE) signals detected from the hydrogen permeation test of a medium strength steel were investigated. The aims of this research are to study the correlation between the AE signals and the severity of hydrogen-induced damages, and to investigate the relationship between the AE signals and the variation in hydrogen permeation current. In this study, an electrochemical approach using Devanathan's dual-cell method was adopted for the hydrogen permeation test. A total of five specimens were tested with a charging current varying from 10 to 60 mA. From the test results, good correlation was observed between the detected AE signals and the severity of the hydrogen-induced blistering and cracking. Also, it was found that the variation in the hydrogen permeation current showed a close correlation with the detected AE energy and events.