Nondestructive Evaluation of Welding Crack Defects in Structural Component Of Track Crane Using Acoustic Emission Technique

On-line defects detection of structural component of track crane such as crane boom, outriggers, turntable and vehicle frame, is a difficult problem of nondestructive testing (NDT). In the present study, the usefulness of acoustic emission (AE) measurements for the detection of welding crack defects in the specimen made of HG70 steel, which is widely used for manufacturing structural component of track crane, has been investigated. Firstly, three-point bending test on the standard specimen made of HG70 steel is conducted. Then the analysis of AE source location and AE source characteristics are introduced respectively. As the result, the rudimentary location analysis can be attained using the linear location method. For AE source characteristics, procedural map of amplitude, RMS or energy rate, energy accumulation map, in connection with the corresponding conditional filter means, are available analysis methods to mirror welding crack defect. We find that the maximum of the amplitude, energy rate and RMS appear approximately at the same time, and the time is the point at which energy accumulation has a remarkable jump as shown in the energy accumulation map. In the end, we deduce that the reason why there is such a sudden energy leap is because of the activities of welding crack, and the multistage energy release also because of the step by step propagation of welding crack.