PROCESS FOR PRODUCING IMPROVED GRAIN REFINING ALUMINIUM-TITANIUM-BORON MASTER ALLOYS FOR ALUMINUM FOUNDRY ALLOYS

摘要

A process is provided for producing aluminium-titanium-boron grain refining master alloys containing soluble titanium aluminide and insoluble aluminium boride particles, the process comprising mixing aluminium-boron alloy powder and K₂TiF₆ salt to obtain a blended mixture, heat treating the mixed powder blend thus obtained in an inert gas furnace just below the melting point of aluminium, at approximately 650 degrees Celcius sufficiently long and compacting the heated powder blend in the form of tablets. The cast grain size of an aluminium-7 wt % silicon foundry alloy after inoculation with this master alloy at an addition level of 0.02% Ti was less than 200 microns for contact times of upto 15 minutes.