The work is aimed at characterizing the properties of slag obtained from CaO-CaF2- TiO2-SiO2 based coatings developed for welding the offshore structures. Extreme vertices methodology was used to formulate coating compositions. Iron ore waste red ochre has been used as source of iron in the coating. The slag has been characterized for thermal stability, density, specific heat, enthalpy of reaction, thermal conductivity behavior, and thermal diffusivity. Welding slag was also structurally analyzed for different phases and bonds. Silicate ion (SiO44−) has been found to influence all the slag properties significantly. Effect of coating constituents has been studied using regression analysis. Mineral constituents and their interactions were found to have influential role on thermo-physical, chemical and structural behavior of slags. © 2020, Springer Nature B.V.