Characteristic of Acoustic Emission Signal from Stress Corrosion Cracking in Low-Carbon Nitrogen-Enhanced Stainless Steel

Abstract

The problem of stress corrosion cracking (SCC), which causes sudden failure of metals subjected to stress in a high-temperature, high-pressure water environment, is studied. Acoustic emission (AE) monitoring is a promising method for detecting the initiation and propagation of SCC. In this study, pencil-lead breaks are used as AE signal sources to first validate the parameters for the verification of the finite element modeling of microcracking. Then, a simplified fracture propagation model of low-carbon nitrogen-enhanced (316LN) stainless steel is established on the basis of moment tensor theory. Finally, the inner connection between the energy release rate of the AE source and the morphological aspect of crack formation is analyzed. The results of modal analysis show that the amount of energy released by the growing crack is linearly proportional to crack depth. Moreover, their frequency characteristics are almost unchanged from the results of analysis by fast Fourier transform. Therefore, SCC initiation and propagation in 316LN stainless steel can be evaluated by this detection method. Moreover, this analysis method based on the energy release rate of the AE source can also be extended to almost all solid materials and structural crack detection.

A Review on the Applications of Acoustic Emission Technique in the Study of Stress Corrosion Cracking

“…Indeed, comparing the information summarized in Table 2, the wavelet technique is the most common post-processing choice to discriminate AE events. In fact, this investigation strategy was proposed also [94,115,118,124,128,135] in order to assess competing SCC phenomena evolving from metal dissolution and pitting toward crack activation and propagation up to plastic deformation and sample fracture.…”

Acoustic Emission Monitoring System for Hard Polishing of Sapphire Wafer

“…Aguiar et al (9) used neural networks to predict the surface roughness of ground workpieces on the basis of the analysis of output variables such as AE signals and cutting power. Li et al (10) established a simplified fracture propagation model of low-carbon nitrogen-enhanced (316LN) stainless steel. Besides, they also analyzed the inner connection between the energy release rate of the AE source and the morphological aspect of crack formation.…”