Metalworking № 4 (136)/2023

Material cutting

Naumov A. G., Syrbu S. A., Taratanov N. A., Azovtsev A. G., Krapostin A. A. Microencapsulated oxygen-containing LCTMinfluence on the characteristics of cutting processes in metals and alloys

The article presents the results of resistance tests for cutters made of R6M5 steel using various microencapsulated oxygen-containing LSTM for stainless steel 12H18N10T, chromium steel H40, titanium alloys VT5-1 and VT6 at different cutting speeds. For each type of microcapsules, their optimal concentration in aqueous emulsions was selected. It is shown that for all processed materials the greatest durability of the cutting tool is achieved when water emulsions of microcapsules with gelatin shells with magnetite and ozonized water in the core are used as LSTM. An increase in the durability of the cutting tool when using the studied LSTM is associated with the formation of protective lubricating films immobilized on tribo-conjugated surfaces.

Keywords: steels, titanium alloys, cutting, turning, microcapsules, ozone, lubricating and cooling technological means.

Kizhnyaev Yu. I. Chip breaking control during circular deep hole drilling in chromium — nickel steel shaft parts

Multifactorial dependences of the length of the chip elements on the cutting conditions, the hardness of the material being machined and the dimensions of the chip-compressing grooves are given. The influence of these parameters on chip formation when drilling at constant and variable cutting conditions is studied. Recommendations are given for chip control and an algorithm for selecting the „speed—feed“ combination based on ensuring minimal fluctuations in the length of chip elements.

Keywords: cutting speeds deep hole annular drilling, chip breaking in core during, cutting conditions for deep core during.

Malyshev E. N., Loshkareva E. A. Planning of the metal-cutting tool’s wear resistance based on statistical data

The article presents an example of planning of the metal-cutting tool’s resistance timeframe. It is shown that the actual tool’s resistance timeframe is a variable value due to the dependence on many factors, so the choice of the planned tool’s resistance timeframe should be based on statistical data. A three-parameter Weibull distribution is used for the formal imagine of statistical data. For example, the Laplace criterion, maximum-optimism criterion , Wald criterion , Savage criterion and Hurwicz criterion are determined. On the basis of that criteria a decision can be made on the appointment of a planned tool’s wear resistance timeframe. This approach will be in demand for technological systems working with forced tool replacement and will increase their efficiency through the rational use of the tool’s wear resistance.

Keywords: metal-cutting tool, tool’s resistance timeframe, decision-making, forced tool replacement, statistical data, Weibull distribution.

New materials and technology

Golovkin P. A. On additional requirements for 10864 steel rods for manufacturing parts of electrovacuum devices

Taking into account the use of electrovacuum devices in the details of the working area, and on the basis of an analysis of typical defects in the material of bars made of vacuum-melted steel 10864, additional requirements for its quality are substantiated, which are absent in the current regulatory documents for the supply of these bars.

Keywords: vacuum devices, steel, rods, additional requirements, defects, chemical composition, structure, grain, inclusions, flocks.

Ivanov K. D., Gavze A. L., Zhukov A. S. Optimization of heat treatment modes of high-strength Cr— Ni—Mo—V sheet steel

A study of the influence of pre- and final heat treatment modes on the structure and mechanical properties of sheet semi-finished products made of high-strength medium-carbon Cr-Ni-Mo-V steel was carried out. On the basis of metallographic research and determination of the hardness of semi-finished products, the technological parameters of preliminary deformation-heat treatment were selected, including quenching from rolling heating (TMO) and spheroidizing annealing, which ensure the production of a fine-grained homogeneous pearlite structure with globular and evenly distributed carbide phase secretions. As a result of studies of the effect of temperature and heating time for quenching, the type of cooling medium, temperature and heating time at low tempering on the structure, phase composition, hardness, mechanical properties under tension and impact bending, the optimal parameters of the modes of final heat treatment of billets from the steel under study for the manufacture of parts operating under conditions of intense shock and cyclic loading at temperatures up to minus 60 °С were determined.

Keywords: sheet semi-finished products, high-strength steel, deformation-heat treatment, microstructure, mechanical properties.

Efremova E. S., Vasilkov D. V. Modification of the rod surface of the power hydraulic cylinder by the method of vibration rolling

The features of modification of the shaft surface of the power hydraulic cylinder shaft by surface plastic deformation by the method of vibration rolling are considered. The aim of the work is to develop a technological solution for the formation of a continuous regular microrelief on the surface of the shaft after finishing turning and electrolytic chrome plating operations. This technology replaces grinding and polishing operations, especially after chrome plating. The specified, selectable and calculated design and technological parameters are highlighted, the variation of which makes it possible to form a continuous regular microrelief of the functional surface. The kinematics of formative movements during vibration rolling is investigated. The frequency of rotation of the shaft, the width of the vibration track, the angle of overlap, etc. varied in the selected ranges. Based on parameter control, a continuous regular microrelief of the shaft surface has been formed that meets the quality requirements. For technological modes that do not provide continuity of the regular microrelief, the completeness of the coating is achieved on the basis of a small variation of parameters. At the same time, processing performance increases by 50% or more.

Keywords: surface plastic deformation, vibration rolling, continuous regular microrelief, shaping movements, kinematics, control of vibration rolling parameters.