Early damage identification method of 2.25Cr-1Mo steel based on acoustic emission statistics
WANG Xueqin;QIU Feng;PENG Ningwei;YAO Junyu;ZHANG Ying;College of Safety Science and Engineering, Changzhou University;Qingdao Institute of Safety Engineering,Sinopec;
Crack cracking is one of the common damage failure forms of metal materials, and material failure will experience the dynamic evolution process of microstructure from early micro damage to macro deformation.How to find the damage as soon as possible before the macro deformation of materials is very important.Based on the mechanism analysis of different sound sources in the process of material damage and failure,this paper puts forward the variable of the statistical ratio κ of different sound source signals to determine the discrimination index characterizing the early damage stage of materials. Six 2.25Cr-1Mo steel specimens without surfacing layer and with surfacing layer with different defects were prepared, and the whole bending damage process of the specimens was tested online by acoustic emission technology. The acoustic data of six specimens in the early damage stage were obtained. By comparing and analyzing the statistical results of single parameter dominated by amplitude and energy and multivariate parameter κ based on support vector machine(SVM), it is demonstrated that κ value can effectively distinguish the early damage stage of 2.25Cr-1Mo steel specimens without surfacing layer and with surfacing layer. The κ value range of specimens without surfacing layer is 1 : 3.1–1 : 3.6, and the κ value range of specimens with surfacing layer is 1 : 2.2–1 : 2.6.
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