For TiO2–SiO2–MgO and SiO2–MgO–Al2O3flux system, the thermophysical and physicochemical behaviour of submerged arc slags studied. Slag plays an essential role in shielding the weld joint from atmospheric contamination. The mass percentage of each flux ingredient evaluated by the X-ray fluorescence technique. Twenty-one slags developed based on the mixture design approach. Thermogravimetric, DSC, and Hot-disc techniques used to analyze submerged arc slags. Thermogravimetric & DSC analysis was performed from 25 ºC to 900 ºC to find the thermal properties. The density measurement of slag performed at ambient temperature. Bond-behaviour was studied by Fourier transform infrared spectroscopy (FTIR) technique. Regression models for different slag properties developed. The multi-objective technique utilized to optimize different slags. © 2020 CIRP