PROPERTIES AND STRUCTURE OF CAST IRON MODIFIED BY LGM TECHNOLOGY

Procesi littâ, 2024, Vol 2 (156), 29-37

Abstract

The influence of complex modifiers containing magnesium, REM, TiN2--TiC on the structure and quality of cast iron castings produced by the method of casting on gasifiable models (LGM) has been studied. The research has established that this method of metal modification in the casting mold is progressive and promising in the direction of development of technology for production of
quality castings from high-strength cast iron with spheroidal graphite, which practically excludes oxidation of modifiers by air oxygen. In this case, in-mold modification is characterized by a number of technological advantages: a significant increase in physical and mechanical properties and overall quality of castings, as well as reducing the cost of their production. The ratio between the used elements providing increased service life of castings made of modified cast iron is determined. The phase composition of modified cast irons is slightly different from cast irons obtained without modification, and is mainly represented by the main α-Fe phase, weak peaks of carbide phases - cementite Fe₃C, silicon carbide SiC, as well as free carbon. A slight increase in the lattice parameter of modified cast irons was established, due to the dissolution of modifier elements in α-Fe, which also contributes to the strengthening of the metal base - the matrix. Carbon in the X-ray spectra of modified cast irons is recorded somewhat differently than in the X-ray image of the original sample (unmodified), not in the form of a clear reflex, but as a series of weak blurred peaks characteristic of dispersed structures, which indicates the spherical shape of carbon in modified cast irons.