Prysyazhnyuk P. The regularities of forming structure and properties of carbide steels based on Hadfield steel

The thesis is devoted to solving of an actual scientific and technical problem - creating of carbide steels with capable to deformation strengthening Hadfield steel austenite binder. The fundamental regularities of interfacial interaction during infiltration of Mo2C, VC and NbC porous skeletons by molten steel grade 110G13L, formation of phase composition, structure and properties. It is shown, that using NbC as a carbide phase allows obtaining by infiltration carbide steels with high level of mechanical and operating prop-erties due to almost complete preservation of the composition of the initial components and complete wettability of carbide grains by steel melt. It was ascertained that maximum value of bending strength for NbC-Hadfield steel is attained for binder phase content ~ 40 % (by volume). Developed carbide steels characterized by the ability to strengthening during surface plastic deformation due to work hardening binder and their wear resistance in friction on fixed abrasive conditions is higher than for 110G13L steel in ~ 3.5 times. It is shown, that during surfacing by ESD with carbide steels obtained layers has hetero-phase structure, thickness ~ 60-80 microns and microhardness ~ 10-11 GPa. Experiment-industrial test showed the feasibility of using developed carbide steels for strengthening the working elements of earth-moving machinery and die tools.