Features of the Technological Process of Manufacturing Two-layer Cast Iron Castings with Differentiated Properties

Processy litʹâ, 2019, Tom 134, №2, p.15-20

Abstract

Received 15.03.2019

UDK 621.74

A brief review of the class of construction materials is presented as materials with differentiated properties, the tendency of which in industry is constantly increasing. Their main properties, their areas of application and advantages in use are given. On the basis of the proposed technology for producing castings with differentiated properties from cast iron, an analysis of the process parameters is carried out. The basic principles of the technology of the inmold modification and the choice of the granulometric composition of the modifier and the general configuration of the gating system are described. The conditions and results of the experiment to work out the technological parameters of the process of obtaining a cast-iron two-layer casting with differentiated properties for working in abrasive conditions are presented. The parameters of the technological process are established under which the required microstructure and mechanical properties are obtained in the casting, namely the creation of such conditions under which, after the first casting stage, cast iron crystallizes in a metastable system with chilling in the working casting layer, after the second stage of casting, – in a stable system with the formation of the microstructure of gray iron with inclusions of lamellar graphite. With the help of metallographic analysis, transition zones, which are formed at the junctions of the cast iron layers, and the layers themselves, namely their sizes, the morphology of graphite and cementite inclusions, and the metal matrix, are investigated. The mechanical properties of the structural components were established both in the transition zone and in each layer separately, and their number in the same parts of the casting was also established.