Acoustic emission during monotonic and cyclic fracture toughness tests of 304LN weldments

Fracture Toughness Evaluation of 316LN Stainless Steel and Weld Using Acoustic Emission Technique

“…5,7,8,25,27) In 7075-T651-Al alloy, the critical values of K and J determined with the help of AE technique were approximately 6-10% lower than the values estimated by the conventional procedure. 25) Ohira et al have reported that the fracture toughness J QAE of A533B pressure vessel steel was nearly 36% lower than that obtained by conventional J-integral test.…”

“…Nevertheless, in other works, the maximum value of AE parameters such as amplitude and frequency spectra was used to evaluate the fracture toughness. [4][5][6][7][8][9][10] In A533B pressure vessel steel, the first appearance of high amplitude emissions appeared to be associated with crack initiation and extension, which involved the rapid shear linkage of growing void. 4) In C-Mn structural steels, two distinct peaks in the variation of total AE events with time were observed during fracture toughness tests.…”

“…Moreover, in the case of 304LN weldments, AE behavior was investigated during monotonic and cyclic fracture toughness tests and the sudden rise in AE energy associated with high amplitude signals was taken as the crack initiation. 8) In addition, double differential based on AE count was used to evaluate the fracture toughness of SA333 Gr.6 steel for the first time. The maximum rate of occurrence of AE at a point had been correlated with the crack initiation point.…”

“…Several authors have attributed this sudden rise of cumulative parameters with high amplitude signals to crack initiation. 5,7,8) However, the crack initiation was not physically verified. In this investigation, the potential drop of specimens during fracture toughness tests were obtained to provide some evidences, as presented in Fig.…”

“…For utilizing this ability of AE, several investigators have performed extensive fracture toughness tests by AE technique to estimate the fracture toughness values. [1][2][3][4][5][6][7][8][9][10][11] However, the approaches are different. In some investigations, changes in the slope of AE parameters versus fracture mechanic parameters such as crack opening displacement…”