Process analysis and optimization for failure energy of spot welded titanium alloy

•RSM was used to develop the numerical model between failure energy and variables.•Analysis of variance was used to certify the developed models.•Effect of welding parameters on mechanical behavior of welded joints was discussed.•Increasing the electrode force will decrease failure energy of the welded joint.•Artificial fish-swarm algorithm was applied to optimize the failure energy.

Titanium and its alloys have been applied in many industrial fields because of their high specific strength, good corrosion resistance and high thermal stability. Whereas, there is limited valuable references for recommendations of welding parameter selection and specific standards of the small scale resistance spot welding (SSRSW) of titanium alloy though it has been applied in many industrial production fields. Seventeen tests were designed according to the three-level three-factor Box–Behnken experimental design and the mathematical model correlating the process parameters and the failure energy was established on the basis of response surface methodology (RSM) technique. And then this model was used to analyze the effects/interactions of the welding parameters on the failure energy. The verification test results which were conducted with completely new welding parameters verified that the model presented in this paper was effective and robust. Sensitivity analysis was also carried out to explore the impact of each process parameter on the quality of welding joint. The optimal combination of process parameters for maximum failure energy of the welded joint was obtained using the model based on artificial fish swarm algorithm (AFSA).