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

Abstract

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, Al₂O₃, and SiO₂ positively influences the transfer of nickel from the electrode to the weld pool. Increased levels of Na₃AlF₆, SiO₂, and CaO positively affected chromium transfer, while Al₂O₃ led to a decrease in chromium transfer. Manganese transfer was enhanced by CaO and Na₃AlF₆, but reduced with higher concentrations of Al₂O₃ and SiO₂. Furthermore, an increase in SiO₂ raised the oxygen potential, contributing to a loss of manganese in the Weld. The results indicate that increasing Al₂O₃ positively affects iron transfer, while higher concentrations of Na₃AlF₆, SiO₂, Al₂O₃, and CaO improve niobium transfer. Microhardness increases with higher levels of CaO, Na₃AlF₆, and SiO₂, although Al₂O₃ 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.

Graphical abstract

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