Optimization of process parameters for friction weld steel tube to forging joints

Highlights: • Optimization of friction welding on steel tube/forging joints is inspected. • The relationship between the welding parameters and the mechanical properties is developed via response surface methodology. • The tensile strength and elongation (%) is maximized and petal crack length is minimized by using desirability function method. • Petal crack test is used as a complementary method for identifying the quality level of friction welding together with the tensile test. • A confirmation test is conducted using the optimum values obtained through the response surface methodology. In this study, structural durability of continuous drive friction welding (CDFW) of steel tube/forging joints is inspected. The relationship between the welding parameters and the mechanical properties is developed by using response surface methodology (RSM). While keeping rotation speed constant, friction pressure, friction time, forging pressure and forging time are used as input variables, and the tensile strength, elongation (%) and petal crack length are selected as output variables. For setting optimum condition parameters, the desirability function is used. According to the confirmation experiment, the difference between the values of tensile strength, elongation (%) and petal crack length, predicted by response surface curve and the experimental data for the maximum desirability is 1.06%, 13.37% and 2.44%, respectively. Furthermore, the predicted model looks reasonably accurate based on the analysis of variance (ANOVA). Using the response curve, one may estimate the tensile strength, elongation (%) and petal crack length for similar joints. In comparison to previous studies, optimization of CDFW parameters for forging bracket to steel tube joints is investigated for the first time. Petal test for the optimization of friction welding is also utilized for the first time.