Hari Babu Nadendla

Grain Refiner for Aluminium-Silicon Sand Casting Aloys

Al-Si alloys exhibit large grain structure when Al-Si alloy melt is solidified in sand moulds due to low cooling rate provided by the mould. Ti-based grain refiner (Al-Ti-B) is known to be less-effective to refine grain structure of Al-Si alloys due to formation of Ti-Si phase. Recently, we have developed an effective novel grain refiner (NGR) for aluminium-silicon sand casting alloys. Effectiveness of grain size under slow cooling conditions has been investigated. For comparative purposes, a range of sand casting alloys with NGR addition have been produced. The results show that the addition of novel grain refiner reduces the grain and eutectic size significantly for all these alloys at lower cooling rate <0.5 °C/s. As a result of fine primary Al grains, the porosity and elongation in the solidified alloys is notably improved.