Possibility of using unshaped thermal insulation of aluminum alloy castings

The possibility of using diatomite from the Ilyinsky deposit as an unshaped thermal insulation for open risers of castings from aluminum alloys of different alloying systems: technical aluminum A5, AK7, AMg10, VAL10 has been studied. It was found that when the continuity of the oxide film on the surface of a diatomite particle is broken, an exchange reaction occurs with the formation of a silicon transition layer. Since silicon is wetted by aluminum, the diatomite particle sinks in the melt, forming a blockage. As a criterion for the continuity of the oxide film, it is proposed to use the Pilling‒Badworth factor of the alloy components. It has been shown that a high level of the Pilling‒Badworth factor, even at a low content of the component (~ 1 %), leads to the formation of blockages. Ill. 6. Ref. 12. Tab. 1.