Evaluation of Tensile Strength of Spot Welding in DP590Steel SheetsUsing Ultrasonic Wave Attenuation

Spot welding is a type of resistance welding that is used to weld sheets. In this method, the pressure of the electrodes and the heat generated by electrical current lead to welding two or more sheets. Although the use of ultrasonic waves is one of the most common methods for assessing the accuracy of spot welding, in this study, the mechanical properties of the weld, such as the tensile strength of the spot weld, is studied with ultrasonic waves attenuation. For this purpose, spot weldingis created in sheets of DP590 by changing the electric current parameter in the range of 11 to 14 kA. Then the ultrasonic waves with the frequency of 10 MHz passed through the spot weld and then the ultrasonic waves attenuation is measured. After that, by using tensile-shear test, the strength of the spot welding is measured. The microstructure of the welds has also been studied by electron microscopy. The results show that there is a direct relationship between ultrasonic wave attenuation and tensile-shear strength, so that with increasing ultrasonic wave attenuation, spot welding strength decreases, which can be attributed to the change in spot welding microstructure.