Study On Acoustic Emission Detection Of Stress Corrosion Cracking Of Nuclear Plant304Stainless Steel

In order to solve current seriously power shortage crisis, nuclear power waslaunched as a kind of substitution for traditional power generation, because of itsunlimited capacity and high effective application. However, with expansion ofindustrial nuclear power, its safety problem causes people’s consistent attention. Largeamounts of evidences and scientific analyses indicate us that the stress corrosioncracking plays vital role for equipment performance and potential accident in nuclearpower plant. Therefore, a perfect on-line industrial corrosion detection technique isnecessary to prevent the nuclear power from corrosion.Based on the progress of dynamic corrosion detection, in this paper, we forcesour attention on the stress corrosion cracking of304stainless steel applied as keyequipment material in nuclear plant under the condition of acoustic emissiontechnique. The main content is divided as following:(1) Based on the acoustic emission detection technique, this paper we study thedeveloping law of304stainless steel intergranular stress corrosion cracking, also wecontrast our results with traditional electrochemical detection one to prove that ouracoustic emission technique can estimate the corrosion degree effectively andaccurately.(2) Based on the acoustic emission detection technique, we study the developinglaw of304stainless steel transgranular stress corrosion cracking and contrast ourresults with traditional electrochemical one to prove that the acoustic emissionsignals’ activity can be obviously used to divide corrosion progress into differentstages.(3) We study the analysis and processing methods of acoustic emission signals,including the scatter matrix, self-organizing feature map network and K-meansclustering cluster algorithms, to abstract the feature of acoustic emission signalsduring the corrosion process, do clustering analysis and generalize the signals’ typicalcharacteristics of different types. The different corrosion patterns of stress corrosioncracking are distinguished accurately with the signals processing method and theresults shows that the acoustic emission signals of the intergranular stress corrosioncracking mainly originates in the dissolution along susceptible grain boundaries, the plastic deformation ahead of the crack tip and the mechanical fractures of materialligaments, while the sources of acoustic emission signals during transgranular stresscorrosion cracking stems from the pitting, cracking, and bubble break-up separately.