Multi-objective optimization of the process parameters for friction welding of dissimilar metals

This paper presents a multi-objective optimization method for optimizing the process parameters during friction welding of dissimilar metals. The proposed method combines the response surface methodology (RSM) with an a genetic algorithm (GA) method. Ultimate tensile strength (UTS), flash diameter and the heat affected zone (HAZ) width of friction welded nodular cast iron with low carbon steel joints were investigated considering the following process parameters: friction pressure (FP), friction time (FT) and upsetting pressure (UP). Mathematical models were developed and the responses were adequately predicted. Direct and interaction effects of process parameters on responses were studied by plotting graphs. In the case of UTS, FT has high significance followed by: FP and UP. Friction time has high significance on the flash diameter of nodular cast iron followed by UP and FP. However in the case of the low carbon steel flash diameter, UP has high significance followed by FT and FP. In the case of the HAZ width for nodular cast iron and low carbon steel side, friction time has high significance followed by UP and FT. Multiobjective optimization for maximizing the tensile strength and minimizing the flash diameter and the HAZ width was carried out using mathematical model