Aluminium alloys are now used for various purposes in different industries like Automobile industries, Aerospace industries etc. The light weight of aluminium allows producing high strength to weight ratio materials. But these alloys are highly oxidising in nature which is responsible for poor casting products and thus deserves more research to develop the casting design. In this book the reliability of cast Al alloy, i.e. Al-7Si-0.6Mg (LM25), has been investigated using Weibull Modulus. The degree of degassing, ingate velocity are selected as the foundry variables to inspect their effect on the mechanical properties of castings. The ultimate tensile strength (UTS) values are then used to calculate the weibull Modulus which is the indicative parameter for casting reliability; the higher the Weibull Modulus, the higher the reliability of the casting. Gate velocity or the turbulence flow of the liquid metal in the mould has been found to have the second most detrimental effects on casting reliability. This book can help the various manufacturers, researchers to understand the appropriate casting design for sound casting of Aluminium alloys.