OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 Introduction Non-vacuum electron beam surfacing makes it possible to obtain compositions consisting of a base metal and a surface-modifi ed strengthening layer of various thicknesses containing boride particles. The thickness of the layer is regulated by the parameters [1–12]. In the process of non-vacuum electron beam surfacing, it is necessary to use fl at blanks with a thickness of at least 9 mm as the base material, in order to exclude warping during surfacing of the powder mixture. The large thickness and shape of the surface to be strengthened limit the possibilities of various surfacing options. For example, for drilling wells in the oil and gas industry, telemetry systems are used to monitor the condition and direction of movement of drilling tools, the parts of which have a complex structure with cylindrical and shaped surfaces. Chromium-nickel austenitic steel with non-magnetic properties is used as a material for these parts, which are operated in conditions of corrosive environments and abrasive eff ects of rock particles. Increasing the hydroabrasion wear resistance of the surface layers of such products (the inner surfaces of body parts, pipes and valves of telemetry systems) while maintaining chemical resistance and the absence of magnetization is an important technical task [13–15]. The use of hot plastic deformation of compositions consisting of relatively ductile austenitic steel and a wear-resistant modifi ed layer makes it possible to obtain thin-sheet products and products with shaped surfaces that will combine high corrosion and wear-resistant properties [16–20]. The purpose of this work is to study the eff ect of hot plastic deformation on the structure and phase composition of “modifi ed layer – base metal” compositions obtained by non-vacuum electron beam surfacing of a powder mixture of boron and chromium on chromium-nickel austenitic steel 0.12 C-18 Cr-9 Ni-Ti. The goal requires solving the following tasks: – to obtain blanks from austenitic stainless steel strengthened by the method of non-vacuum electron beam surfacing of powder mixtures 10Cr- 30B; – to evaluate the eff ect of the degree of plastic deformation on the structure and properties of boride layers; – to investigate the eff ect of hot plastic deformation on the phase composition and lattice parameters of the modifi ed layer. Research methodology To create a modifi ed layer on 0.12 C-18 Cr-9 Ni-Ti steel reinforced with boride particles, a powder mixture (Table 1) was surfaced with a beam of relativistic electrons released into the air atmosphere using an industrial electron accelerator ELV-6 at the Budker Institute of Nuclear Physics SB RAS. The parameters of non-vacuum electron beam surfacing are presented in Table 2. It should be noted that austenitic steel was used as a reference material in durometric studies. After non-vacuum electron beam surfacing, the specimens were subjected to hot plastic deformation at 950 °C on a Quarto rolling mill with a working roll diameter of 330 mm, a speed of 60 mm/s, a deformation Ta b l e 1 Composition of the powder mixture Name of the powder system The composition of the powder mixture, wt. % Cr B MgF2 * 10Cr-30B 10 30 60 The size of the powder particles, μm 5–20 40–80 200–300 * Since the surfacing is carried out without the use of vacuum and protective gases, MgF2 was used as a fl ux.
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