An investigation of the acoustic emission generated by various crack propagation modes in 304 stainless steel

The present investigation has shown the effectiveness of making careful acoustic emission measurements in conjuction with in-depth metallographic analysis, in order to fully investigate and characterize the various crack propagation modes in 304 stainless steel.;Acoustic emission measurements were made during different types of crack propagation in the 304 stainless steel. The crack propagation modes were changed by a combination of heat treating the material and cathodically charging it with hydrogen. The various crack propagation modes could be identified by their acoustic emission characteristics. The acoustic emission parameters which provided the most information were the acoustic energy and power spectra. A very significant result was obtained regarding the hydrogen degradation mechanism in 304 stainless steel. The result of this investigation indicates that the hydrogen degradation mechanism in 304 stainless steel is the lowering of cohesive energy.