PREDICTION OF MECHANICAL PROPERTIES AS A FUNCTION OF WELDING VARIABLES IN ROBOTIC GAS METAL ARC WELDING OF DUPLEX STAINLESS STEELS SAF 2205 WELDS THROUGH ARTIFICIAL NEURAL NETWORKS

Dual-phase duplex stainless steel (DSS) has shown outstanding strength. Joining DSS alloy is challenging due to the formation of embrittling precipitates and metallurgical changes during the welding process. Generally, the quality of a weld joint is strongly influenced by the welding conditions. Mathematical models were developed to achieve high-quality welds and predict the ideal bead geometry to achieve optimal mechanical properties. Artificial neural networks are computational models used to address complex nonlinear relationships between input and output variables. It is one of the powerful modeling techniques, based on a statistical approach, presently practiced in engineering for complex relationships that are difficult to explain with physical models. For this study robotic GMAW welding process manufactured the duplex stainless steel welds at different welding conditions. Two tensile specimens were manufactured from each welded plate, resulting in 14 tensile specimens. This research focuses on predicting the yield strength, tensile stress, elongation, and fracture location of duplex stainless steel SAF 2205 welds using back-propagation neural networks. The predicted values of tensile strength were later on compared with experimental values obtained through the tensile test. The results indicate <2% of error between observed and predicted values of mechanical properties when using the neural network model. In addition, it was observed that the tensile strength values of the welds were higher than the base metal and that this increased when increasing the arc current. The welds' yield strength and elongation values are lower than the base metal by 6%, similar to 9.75%, respectively. The yield strength and elongation decrease might be due to microstructural changes when arc energy increases during the welding.

Automated summary

The use of artificial neural networks in predicting the mechanical properties of duplex stainless steel welds has shown promising results, with less than 2% error between predicted and experimental values. It was observed that the tensile strength values of the welds were higher than the base metal and increased with increasing arc current. Additionally, the yield strength and elongation values of the welds were slightly lower than the base metal, possibly due to microstructural changes during welding with increased arc energy.