Justification of the choice of the rational method of casting customs from deformable aluminum alloys

Processy litʹâ, 2021, Tom 144, №2, p.31-36

Abstract

Received 29.03.2021

UDK 621.74

The purpose of the work is to create scientific bases for the choice of a rational method of casting shells from aluminum alloy type AMg6M. A review of the main methods of casting aluminum alloys. The advantages and disadvantages of the known methods of casting and their influence on the quality of shells made of aluminum alloys are analyzed, as a result of which a rational method of casting shells made of aluminum alloy type AMg6M is proposed. The choice of a rational method of casting shells from deformable aluminum alloys is substantiated on the example of AMG6M type alloy. The rational choice of the method of shell casting depends on the specific requirements for the shell, taking into account the criteria for maximizing technical and minimizing economic indicators. Experimental researches of technology of casting of shells in a mold with check for hot brittleness are carried out and the received results of experiments are analyzed. It was found that the vibration treatment of the mold during casting leads to improved shedding of the mold, compaction of the metal structure, but complicates the separation ability when removing the casting from the mold. Characteristic features of separating coatings for releasing castings from graphite and zirconium molds have been established. It was found that for complete shedding of the mold, pouring aluminum alloy AMg6M in the mold must be carried out with overheating to 740 ⁰C; It is established that to avoid cracks, the internal form must be heated to a temperature not exceeding 500 ⁰C; It was found that underfillings occur at low temperature of the melt and the mold before pouring or low pour rate. It is established that cracks occur due to high overheating of the melt and prolonged cooling of the casting in the mold. It is determined that shrinkage defects (shells, shrinkage, porosity) occur due to violation of directional hardening and insufficient nutrition of the casting, due to overheating of the mold. Given the prospects and rationality of the technology of casting sealed cylindrical shells from materials of the Al–Mg system (AMg6M) in the mold, this method of casting encourages further research.