Effect of ion nitriding by glow discharge on the physical and mechanical properties of the plastically deformed tool steel R6M5

This work is devoted to the study of the effect of the duration of ion nitriding by glow discharge on the physical and mechanical properties of tool steel with different initial structure. We used specimens of R6M5 tool steel with a coarse-grained structure obtained after annealing at a temperature of 850°C and with a fine-grained structure obtained after severe plastic deformation by torsion discharge. With an increase in the duration of ion nitriding, the thickness of the hardened layer and wear resistance increase. The combination of plastic deformation with ion nitriding by glow discharge increases the adsorption and diffusion rate of the saturating element due to the creation of a highly fragmented and disoriented fine-grained structure and contributed to reduction in processing time.

Methodology for Calculating Heat Loss in the Study of Friction Stir Welding

Currently, the most promising high-tech and productive process is friction stir welding. An important element of this technology is the determination of the material temperature in the stir zone, which can be determined by calculation based on the amount of heat input introduced into the welding zone. To determine this value, experimental of the dependence of heat input on the tool rotation speed and welding speed were carried out. For this, a scheme of experiments has been selected in which the material to be welded (aluminum alloy AMg5) is modeled as an experimental tube with a diameter of 20 mm, and the tool (made of tool steel R6M5) is modeled as a working plate. On the designed and manufactured stand, studies of the dependence of the heat-liberation value for the speeds of rotation of the experimental tube 42-105 rad/s were carried out. In this case, due to the pressing force of the experimental tube and the working plate, a constant temperature of the place of friction was maintained. The obtained experimental data were used to calculate the heat-liberation value and heat power on each concentric ring 2 mm wide at the end of the working tool with a diameter of 20 mm, as well as the total heat power for different speeds of rotation and welding.When carrying out experiments on the bench, heat losses were determined by thermal conductivity along the rod on which the experimental tube is fixed, as well as from the working plate made of tool steel through the gasket onto the working table and by convection from the surface of the rotating experimental tube into the environment. The calculation results showed that each of these losses does not exceed 3-10%. These losses are taken into account in the heat supply calculations.

Impact of Electronic Radiation on the Morphology of the Fine Structure of the Surface Layer of R6M5 Steel

In recent decades, great efforts have been made to significantly improve the performance characteristics of high-speed steel using various surface hardening techniques. Electron beam modification is engaging because it has an exceptionally high thermal efficiency and can significantly improve steels’ physical and mechanical properties. This work is devoted to researching the fine structure and changing the structural phase state of the surface layer of R6M5 high-speed steel after exposure to an electron beam. Electron beam treatment of steel R6M5 was carried out on a vacuum installation. The structure and phase composition of P6M5 steel samples were studied by transmission electron microscopy. Determined that after electron irradiation, the steel structure as in the initial state consists of martensite, carbides and residual austenite. After electron irradiation, an increase in the volume fraction of lamellar martensite is observed: the fraction of lamellar martensite in the initial state is 80%, and after irradiation, it is ~90% of the total fraction of α′-martensite. The action of the electron beam led to an increase in internal stresses in α′-martensite. Revealed, the value of the scalar dislocation density in R6M5 steel after exposure to an electron beam is higher than in the initial state. A cardinal difference in the state of the material after exposure to an electron beam is the presence of bending extinction contours in all M6C carbide particles.

Практика омагничивания в постоянном магнитном поле термически обработанных быстрорежущих сталей

The article is devoted to the processing of high-speed steel R6M5 in a magnetic field. Attention is paid to the presence of a domain structure after magnetization. Studies of microhardness after magnetization are carried out. The reversibility of the hardening effect after removal of the magnetic field is determined. The influence of finishing operations of surface layer processing is established.

Features of technology for manufacturing cast toolbills from rapid-cutting steel R6M5

The article presents the results of computer simulation of the crystallization of castings from high-speed steel R6M5, intended for the manufacture of cutters and gear shaping tools in the conditions of OJSC “Minsk Gear Plant”. The use of modeling made it possible to optimize the gating system, reduce this volume of the profitable part by 30–35 % and increase the yield of suitable casting, which made it possible to reduce the consumption of expensive alloying elements introduced into the melt to compensate for burnout during melting and casting.