Investigation of element transfer and microhardness in weld beads using formulated Na ₃ AlF ₆ -CaO-Al ₂ O ₃ -SiO ₂ coatings for SMAW nickel wire

This research investigates the impact of shielded metal arc welding (SMAW) electrode coating flux on microhardness, microstructure, and element transfer. A mixture design approach was employed to formulate the flux compositions, and multi-pass bead-on-plate experiments were conducted. Regression analysis was used to evaluate the relationship between microhardness and weld bead chemistry. The results indicated that the presence of CaO, Al 2 O 3 , and SiO 2 positively influences the transfer of nickel from the electrode to the weld pool. Increased levels of Na 3 AlF 6 , SiO 2 , and CaO positively affected chromium transfer, while Al 2 O 3 led to a decrease in chromium transfer. Manganese transfer was enhanced by CaO and Na 3 AlF 6 , but reduced with higher concentrations of Al 2 O 3 and SiO 2 . Furthermore, an increase in SiO 2 raised the oxygen potential, contributing to a loss of manganese in the Weld. The results indicate that increasing Al 2 O 3 positively affects iron transfer, while higher concentrations of Na 3 AlF 6 , SiO 2 , Al 2 O 3 , and CaO improve niobium transfer. Microhardness increases with higher levels of CaO, Na 3 AlF 6 , and SiO 2 , although Al 2 O 3 has a reducing effect. The welds were further analyzed through microstructural analysis. In addition, artificial neural network (ANN) models were developed, demonstrating improved prediction accuracy compared to traditional approaches.