Temperature and microstructure characteristics of silumin casting AlSi9 made with investment casting method

This work presents the research result of the temperature distribution and the microstructure in certain parts of the field-glass body frame casting made from silumin AlSi9 using the investment casting method in the ceramic mould. It was proved that the highest temperature of the silumin appears in the sprue in which the silumin is in the liquid-solid state, though the process of silumin crystallization in the casting is finished. It was stated that in certain elements of the casting the side opposite to the runner crystallizes and cools fastest. The differences in the rate of crystalline growth and cooling of certain casting elements cause different microstructure in them which can also influence the mechanic properties. It is necessary to state that the temperature of the initial heating of the ceramic mold equal to 60ºC guarantees obtaining of the castings without defects and of little porosity. Incomplete modification of the silumin with strontium causes silica precipitation to appear close to the spherical ones.