Investigation of the Effect of Some Factors on Resistance Spot Welding of DKP Steel Using Response Surface Method

Abstract

Due to many advantages of Resistance Spot Welding (RSW) such as inexpensive, easy to automate, and high-quality joints capability, it is preferred and used mostly in automative industry. In the RSW process, metals are joined based on the contact resistance between the electrodes and metals. During the process, the cause of the welding nugget on the surface is the increase in temperature because of the electrical resistance of the materials and the melting formed. Many factors affect the success of the RSW process. In this research, we investigated the possibility of mild steel (DKP) sheets welding using the RSW method. There important factors, i.e., time, pressure, and current were tested. The results were evaluated by measuring the shear strength of DKPsheets having 1 mm thickness. To reduce the number of experiments, the experiments are designed and carried out according to the Box-Behnken experimental design. It is one of the most useful response surface methods (RSM). It was aimed to find the effects of investigated parameters and their possible interactions on tensile strength of DKP sheets joined by RSW process. Another important purpose was to generate a mathematical model which can be used to estimate tensile strength as a function of tested parameters. As a result, a second-order model which was important statistically was developed and it was capable of to estimate the dependent variable in very high accuracy.