Abstract: This paper presented the handling and analysis of unexpected acoustic emission signals during the acoustic emission testing of a weld-shrunk multilayered high-pressure vessel in service. The testing was conducted using a two-stage pressurization cycle concurrent with the pressure resistance test. During the second stage of pressure retaining, a substantial amount of acoustic emission signals suddenly appeared at two positions on the container. In order to discern the nature of these abrupt signals, the inspection team introduced an additional decompression-pressure boosting pressure retaining phase following the second stage of pressure retaining. By conducting a comprehensive assessment including the characteristic parameters of the monitored acoustic emission signals, source region localization, as well as factors associated with the container's structural attributes, stress-strain behavior during the pressurization process, and inter-layer interactions, it was ultimately concluded that the two instances of sudden signals were caused by insufficient deformation in certain areas during the first pressurization stage, which led to friction between the layers as they underwent coordinated deformation towards uniformity during the subsequent maintenance pressure phase.The conclusion may provide reference for the occurrence of similar phenomena during acoustic emission inspection.

Key words: weld-shrunk multilayered vessel, acoustic emission inspection, burst signal, compatibility of deformation