Aluminodipine conborate phosphate molding and core mixtures for steel and iron castings

Abstract

It has been experimentally established that the introduction of lithium, sodium, and potassium dipinaconborates into a 10 % aqueous solution of monosubstituted aluminum phosphate leads to a sharp decrease in viscosity and limiting wetting angle. Based on the data obtained, it was concluded that the acceptable content of dipinaconborate is 8–10 wt %, at which the viscosity and limiting wetting angle characteristics meet the requirements for the practical use of binders for cold-hardening mixtures in foundry production. It was found that dipinaconborates increase the binding property of monosubstituted aluminum phosphate. At the same time, the binding property of aluminum dipineconborate phosphate compositions increases in the series of dipineconborates: potassium dipineconborate < sodium dipineconborate < lithium dipineconborate. The aluminum dipineconborate phosphate composition is a combination of monosubstituted aluminum phosphate with lithium, sodium and potassium dipineconborate separately. On the basis of aluminum dipineconborate phosphate binders, core and molding cold-hardening mixtures have been developed with the composition, %: sand 2K1O202 (GOST 2138–91) - 80; clay PZ (GOST 3226-93) - 10; aluminum dipineconborate phosphate binder in the form of a 20 % aqueous solution - 10. Aluminum dipineconborate phosphate mixtures were tested for such physical and mechanical properties as durability, friability, mouldability, strength, residual strength and knockout work. The obtained characteristics of the developed mixtures for the manufacture of molds and cores for steel and iron castings meet the requirements of foundry practice and can be recommended for the manufacture of cores and molds cured in cold tooling.