Optimisation by Taguchi’s method of the electrical parameters and geometry of an S32205 duplex weld

Duplex alloys have excellent mechanical properties, as well as resistance to corrosion, but when they are welded, they present a segregation process of the alloying elements that must be controlled by the electrical welding parameters. In this work, an optimisation study is carried out on the electrical parameters for top welding two 3-mm thick flat profiles, where the smallest optimal thermal input is to be obtained. Welding is carried out with an ABB welding robot. The electrical parameters that can be controlled are the intensity and the forward speed; the rest of the electrical variables are regulated by the robot’s control cell. The Taguchi optimisation consists of an L4 matrix of two factors taken in pairs and the objective is to minimise the thermal input, as well as the geometry of the weld bead. In addition, experimental validation tests of the Taguchi model are carried out. The S32205 duplex alloy is a little-known alloy used in welding with the GTAW process and this is the main reason for its selection in this study. The influence of each of the welding variables on the geometry of the welded joint is evaluated as a percentage.