A process is provided for producing an aluminium-titanium-boron grain refining master alloy containing titanium boride and titanium aluminide particles, the process comprising melting aluminium in a silicon carbide crucible in a medium frequency induction or an electric resistance furnace, adding to the melt at a temperature between 750 degrees Celsius and 900 degrees Celsius, KBF4 and K2TiF6 salts, pre-mixed in proportions to obtain a Ti/B ratio of 5 in the melt, gently mixing the salt mixture with the melt without introducing any stirring, transferring the molten alloy to an electric resistance furnace maintained at 800 degrees Celsius, decanting the K—Al—F salt, the by-product of the salt reaction, thoroughly stirring the molten alloy in the SiC crucible with graphite rods before finally casting the molten alloy into cylindrical molds in the form of billets and finally extruding the billet into 9.5 mm rods.