Assessment of the Structural State of Dissimilar Welded Joints by the Acoustic Emission Method

Abstract

In this study, we investigated defect detection in dissimilar welded joints by the acoustic emission (AE) method. The study objects were carbide and decarburized interlayers, which are formed at the fusion boundary between austenitic and pearlitic steels. Diffusion interlayers, as a structural defect, usually have microscopic dimensions and cannot be detected using conventional non-destructive testing (NDT) methods. In this regard, the AE method is a promising approach to diagnose metal objects with a complex structure and to detect microscopic defects. In this paper, the AE signatures obtained from testing defect-free specimens and specimens with diffusion interlayers are analyzed. We found that the AE signature for defective and defect-free welded joints has significant differences, which makes it possible to identify descriptors corresponding to the presence of diffusion interlayers in dissimilar welded joints.

Application of Acoustic Emission to Detect Damage in Composites Materials

“…Among the applications of the AE method for SHM the following can be mentioned; detection of friction [17], detection of friction and the presence of wear in bearings (bearings, roller bearings) due to improper functioning of grease or lubricant, detection of impact in rotating mechanisms due to excessive looseness of the bearing that causes impact [18,19], detection of turbulence in the inspection of tanks under it is the pressure that the presence of excessive leakage causes turbulent flow [20], detection of defects in manufactured parts [21,22], detection of defects in welding [23] and estimation of the life of the structure [24,25]. Also, this method can be used to reveal and locate partial voltage discharges in large transformers [26], research and investigate the properties and characteristics of materials [27], geology [28,29] and research on micro-vibrations [30].…”

Investigation of Acoustic Emission of Cracks in Rails under Loading Close to Operational

“…The effect of "structural noise" from porous collapse in granular Mg-Ho alloys has been investigated in the fundamental works [25,26], and the AE hits corresponding to this process have been characterized and identified with specific values of AE hit amplitudes. A study [27,28] noted that the appearance of AE hits with a short rise time can also be caused by the deformation of the cementite in the structure of high-carbon steel. AE signals similar in waveform to those shown in Figure 5 were obtained in [29] at the elastic deformation stage; the authors explain the appearance of such signals by welding inclusions in the material structure.…”