Yakovenko R. Patterns of phase and structure formation and properties of powder wear corrosion resistant materials "chrome steel - Cr3C2" for constructional purposes

The aim of the work is establishment for regularities of obtainment of wear- and corrosion resistant powder chromium carbide reinforced steel on the basis of "chrome steel - Cr3C2" system using the methods of liquid phase sintering, hot forging and high-speed hot pressing as well as development on their basis of technological schemes for manufacturing of the wares. The research object is powder chromium carbide reinforced steel on the basis of chrome steel Х17Н2, Х13М2 grades mixed with Cr3C2 and TiC. For the first time in scientific practice, on the basis of systematic researches for conditions of obtaining of new type of "chrome steel - Cr3C2" chromium carbide reinforced steel synthesized by the method of liquid phase sintering, hot forging and high-speed vacuum hot pressing. The features of interaction between Cr3C2 and the steel chromic matrices of ferrite and ferrite- martensite classes in the process of heating were discovered and explained. It is determined that the interaction between solid and metallic constituents consists not only of the dissolution of carbide components (Cr and C) in a steel matrix and components of chromic steel (Fe) in the carbide of chrome but also in the crystal-chemical converting of Cr3C2 into the difficult Fe-Cr carbides of type Me2C, Me7C3, Me23C6. It provides the increasing of maintenance of carbide phase and formation of complex heterophase structure of chromium carbide reinforced steel and leads to enhancing of their physical-mechanical properties, wear- and corrosion resistance. Established that for saving of fine-grained structure and giving high mechanical and operating properties to wares based on developed chromium carbide reinforced steel it is necessary to use the high-speed methods of hot compression. In its case smallest degree of interaction between initial components also occurs. The results of Ph.D. degree work have been successfully approbated and introduced as hammers of shredder forage in the experimental sector of the separated subdivision of National University of Life and Environmental Sciences of Ukraine "Agronomic Research Station".