Kovalchuk O. Features of making castings with differential surface properties

The dissertation has solved the urgent problem of saving expensive alloys for the manufacture of wear-resistant and heat-resistant castings from alloys based on iron using surface alloying technology instead of traditional volume alloying technologies. In addition, individual parts of the casting acquire those properties that ensure their further long-term operation. It is established that the main technological parameters of the process are the fractions of ferroalloys, their melting temperature and the pouring temperature of the alloy, which provide the infiltration of the liquid metal through the alloy coating with its futher melting and mixing in the liquid metal stream. According to the results of the study, it is determined that in order to obtain wear-resistant layer it is necessary to use high-carbon ferromanganese with the addition of ferrotitanium, ferrochrome and ferroboron and for heat-resistant layer ferrochrome and aluminum should be used. The best performance properties of the surface alloy layer were obtained using a bonding component for the alloy coating – liquid glass diluted with water to a density of 1200 kg/m3. The economic impact of the implementation of the developed technology to manufacture foundry products of wear-resistant cast parts is about 13150 UAH per one ton of casting, and heat-resistant cast parts is 23800 UAH per one ton of casting.