Waveform acoustic emission data was from a large size real metal pressure tank during hydrostatic testing. Typical welding defects such as cracks and inclusions were buried in the weld seam of the vessel before hydrostatic testing. Defect burying and hydrostatic testing have been repeated several times and waveform acoustic emission data were collected during those hydrostatic testing. Before and during hydrostatic testing all buried defects were confirmed by ultrasonic testing and magnetic particle testing. After hydrostatic testing and before defect reburing the defects buried last time were confirmed by opening the weld seam and magnetic particle testing.

Investigation of modern spectral analysis for waveform acoustic emission data shows that the selection of modern spectral analysis has very strong influence on the ability of analysis. Some modern spectral analysis methods show a very promotive result and others show a poor analysis result. Comparing different modern spectral analysis methods and FFT analysis method has been and the result has been discussed. REFERENCES

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