Research on the In Situ Tensile Fracture Behavior of Q355E Steel and Its Welded Joints Based on Acoustic Emission

The meso-damage process of Q355E steel metal used in wind power tower is accompanied by the release of transient stress wave. The information of stress wave can be collected by acoustic emission detection technology. However, due to the lack of intuitive and visual means, it is difficult to quantitatively evaluate the meso-damage of metal materials by acoustic emission information. In this paper, Deben Microtest 2kN in situ tensile test bench, FEI Quanta 450 field emission scanning electron microscope and SAEU2S acoustic emission acquisition system are combined to build a dynamic observation experimental system of acoustic emission source. The results show that there is a good correspondence between the in situ tensile displacement-load curve and the amplitude history of the acoustic emission signal. At different stages of in situ stretching, the acoustic emission signal has characteristic signals. The changes of the microstructure of the samples were observed, and the characteristic acoustic emission signals during the stretching process were analyzed by parameter analysis and waveform analysis.