Element Transfer Behaviors of Agglomerated CaF2-ZrO2 Fluxes in EH36-Shipbuilding Steel Subject to High-Heat Input Submerged Arc Welding

Abstract

EH36-shipbuilding steel has been welded by CaF₂-ZrO₂ fluxes with designed ZrO₂ additions. Possible chemical and electrochemical reactions have been postulated to analyze alloying element transfer behaviors. The decomposition of ZrO₂ during SAW has been validated by applying the gas–slag–metal equilibrium model and the O supply capacity of ZrO₂ has been quantified. For the entire compositional range, O content has been controlled within a well-maintained range from 220 to 400 ppm, and the transferred quantity of Zr content reaches to the maximum value of 120 ppm. It is further demonstrated that ZrO₂ addition incurs appreciable Si loss within the weld metal.