Zahrebelnyi V. Technological providing of high wear resistance of high-speed steel R6М5 by combined methods of surface hardening

The thesis was solved the actual scientific task of increasing the wear resistance of surface layers of high-speed steel R6M5 by the combined methods of applying wear-resistant coatings by establishing patterns of influence of their structural-phase composition, physical-mechanical properties and parameters of structe on tribotechnical characteristics. The regularities of the formation of the structure of steel R6M5 after discretely laser treatment and nitrated, depending on the schemes of the previous laser treatment and the technological parameters of nitriding, were established. Proposed the mechanism of increasing the wear resistance and stability of the cutting tool made of steel R6?5 by discrete laser treatment under the cellular scheme with the nitriding, in accordance with which combined thin, plastic nitrogen-free areas without laser treatment, which shield the direct contact of the cutting tool and machined part and provide the process of wearing-in and strengthened by a laser with a high hardness of the site and increased wear resistance. The connection between the wear resistance of combined coatings in the conditions of abrasive deterioration and the stability of the cutting tool during operation is established. Combined coatings with a higher abrasive durability ensure higher stability of the cutting tool. It is proposed to determine the design factors of coatings on a cutting tool made of steel of R6M5 of discrete and gradient types on the basis of experimental research in the conditions of slipping friction and abrasive wear and results of calculations of stress-strain state that arises when friction of the working surface of the cutting tool.