Research on fatigue crack propagation of micro-alloyed steel by acoustic emission

Abstract

This study focused on fatigue crack propagation of Q345 steel in tests using acoustic emission technique. The fatigue tests of the Q345 steel plate specimens were monitored with acoustic emission, and acoustic emission amplitude, energy and counts were obtained. According to the acoustic emission features, the fatigue crack growth was divided into three parts: primary stage (amplitude of 42–51 dB and energy of 1–10 V μs), steady stage (amplitude of 42–73 dB and energy of 1–80 V μs) and rapid growth stage (amplitude of 42–84 dB and energy of 1–170 V μs). The results showed that acoustic emission could be used as a non-destructive testing method to monitor and analyse the fatigue deformation of micro-alloyed steels because acoustic emission is relatively sensitive to fracture mode changes.