PRODUCTION OF CASTINGS FROM LIQUID-SOLID AND SOLID- LIQUID ALLOYS
Rheo- and thixolite technologies, which are increasinglybeing used in the manufacture of castings for responsiblepurposes, are the object of extensive scientific and technological research, since their implementation is associated with the need to solve a number of non-traditional tasks. It has been established that injection molding with crystallization under pressure is recommended for the manufacture of the following castings: with increased density, as well as for artistic castings of a complex profile. In the latter case, the forming part of the matrix is made with disposable inserts. Unlike castings made by injection molding, castings made by injection molding with crystallization under pressure can be subjected to heat treatment, which significantly improves the mechanical and service properties of castings and parts. As a result of the impact of pressure on the crystallizing alloy, structural changes occur in the castings (grinding of the structure, changes in the composition and nature of the phase distribution), an increase in uniformity as a result of a decrease in the degree of development of liquation processes, a uniform distribution of non-metallic inclusions and, as a consequence, an increase in physical and mechanical parameters. At the same time (in comparison with other casting methods), an increase in the strength indicators of castings by 15-30% and plastic ones by 2-4 times is achieved. Comparative indicators of mechanical properties in castings made of solid-liquid Md-LPD alloys at an inlet speed of 0.5 m/s are given.