PROCESS FOR CASTING ALUMINUM ALLOYS

摘要

PROCESS FOR CASTING ALUMINUM ALLOYS The technical properties of aluminum alloys, particularly tensile strength, yield strength and elongation percent, can be improved by refining the grain of the casting. For that purpose, particular attention must be paid to obtaining the smallest possible intervals between the secondary dendrite arms. Seeding the melt by adding seeds with a pre-alloy does not bring satisfactory results, particularly with respect to the dendrite arm intervals. Small dendrite arm intervals and good technical values can be reliably obtained by casting the aluminum alloys in a ceramic mold with numerous micro-sized rough spots and pores and applying to the inner wall of the mold after it is dried and fired a thin layer of a salt mixture in which the cations are primarily from alkalis and/or alkaline earths and the anions are primarily from halogens and which has a liquidus temperature lower than the casting temperature of the alloy.