Metalworking № 2 (134)/2023

Investigation of the effect of cutting fluids on the durability of the milling cutter in face milling of heat-resistant steel

1. P. Kozlovsky, K. A. Kosarev, A. G. Kisel

The article describes the results of experimental research of influence of cutting fluids Sinertek MX, Isogrind, Smalta-3*EP on the endurance of a milling cutter at face milling of heat-resistant steel. According to the results of the experiment the dependence of cutter wear on the cutting path when using cutting fluid was determined. Cutting fluid that has the best lubricating effect on the cutting tool and thereby increases its durability has been determined.

Keywords: cutting fluid, metal-cutting tool, milling, durability.

Study of the impact of the rounding radius of a cutting edge on the roughness of a part surface

1. V. Maksarov, M. A. Popov, V. I. Bolobov, V. G. Kufaev

The radius of rounding of the cutting edge is an important geometric parameter of the cutting tool, which has a significant impact on its wear resistance, as well as making a significant contribution to the quality of the processed surface of the product. This parameter of the tool affects the mechanics of the cutting process, is able to change the cutting force and residual stresses on the surface of the product. The formation of the radius of rounding of the cutting edge of the tool is currently of practical importance and depends on a large number of parameters, one of which is the material of the cutting plate or tool. This article examines the effect of the radius of the cutting edge of the replaceable polyhedral plate VOK-60, pre-prepared by magnetic abrasive treatment, on the quality of the treated surface of the product made of hardened steel 45.

Keywords: magnetic abrasive machining, cutting ceramics, ceramic plates, surface quality, surface microstructure, rounding radius, electromagnetic induction, cutting edges.

Calculation of systematic component of primary profile texture of the machined surface

1. G. Chernykh

This paper covers issues related to the formation of the texture profile of the surface of thin-walled machine building parts and the effect of the texture on the properties of the surface layer of parts. To describe the texture of the surface obtained during fine turning, the article considers the composite mathematical model of the primary profile. This model is presented as a trace of a periodically moving cutting tool on a machined surface, depending on the profile of the cutting tool and the cutting modes. A case is considered when the tip of the cutter with radius r, front and back surface and feed S is involved in the formation of the profile component.

Keywords: surface roughness, primary profile, profilogram, measurement, fine turning.

Investigation of the heat resistance of the surface layer of steel 45 subjected to shock electromechanical treatment

1. G. Dudkina, N.G. Sharonov, M.Yu. Vetlitsyn

The results of studies of the influence of high temperatures on the structure and microhardness of the surface layer of normalized steel 45, hardened by electromechanical processing with the dynamic application of a deformation force (impact EMT) are presented. The characteristic features of thedistribution of microhardness and the analysis of the microstructure of the surface white layer of steel in the temperature range 100-600 0 C are considered. The results obtained make it possible to identify the temperature range in which the specific properties of the surface layer subjected to EMT with impact are preserved for parts operating at elevated temperatures.

Key words: steel, surface hardening, shock electromechanical treatment, current density, pulsed deformation, structure, white layer, microhardness, heat resistance.

Metals and alloys of metal-cutting machine parts and features of their application

1. S. Alexandrov, V. V. Golikova, D. V. Vasilkov

Metals and alloys of metal-cutting machine parts and features of their application in the housings of the carrier system, drives and controls are considered. Steels and alloys of various grades and the requirements for strength, hardness and basic modes of heat treatment are considered. Effective methods of chemical-thermal treatment and mechanical hardening are proposed. The features of the use of non-ferrous alloys are considered. The main characteristics of the materials are tied to state and industry standards, as well as technical conditions. The use of modern grades of steels and alloys is distinguished by the presence of specific characteristics of materials related to the specifics of their application and regulatory documents.

Keywords: structural materials, metals, alloys, parts, metal-cutting machines, drives, main characteristics, hardness, heat treatment, chemical-thermal treatment, hardening.

A method for reducing the negative impact of mechanical rolling on the quality of tube bundles when fixing tubes in thick tubesheets of shell-and-tube heat exchangers

1. V. Sannikov

In the production of shell-and-tube heat exchangers, one of the most important factors ensuring their reliability and durability are the connections of tubes with tubesheets. Thick tubesheets are often used in highly loaded heat exchangers to increase the reliability of the connections themselves. A thick tubesheets is a grating whose thickness exceeds the nominal outer diameter of the tube fixed in it by more than 4 times. The article deals with one of the main problems of fixing tubes in thick tubesheets, namely: elongation of fixed tubes in the working cavity of the heat exchanger during their rolling. The lengthening of the tubes between two rigidly fixed tubesheets leads to the curvature of the tubes (or their sagging), which, in turn, causes a decrease in the gaps between adjacent tubes, the accumulation of deposits between them, and worsens the heat exchange process. A new method of forming combined tube connections with thick tubesheets is proposed.

Keywords: expanded joint, thick tubesheets, elongation of tube, tape-screw method, tightness, strength, test sample, experimental evaluation.

Fluctuations in the drives of metal-cutting machines due to unbalance of rotary systems

1. V. Golikova, A. S. Alexandrov, D. V. Vasilkov

The article discusses the fluctuations in the drives of metal-cutting machines due to the imbalance of rotary systems. The main types of vibrations in metal-cutting machines are self-oscillations, forced and parametric oscillations. One of the sources of oscillation of drives and machines in general is the unbalance of rotating systems. They are especially manifested in resonant modes. Therefore, an important task is to search for high-quality dynamic circuits and detuning technological modes from resonances by shifting the main frequencies of natural oscillation forms to the right or left. it is established that the unbalance of the masses in the rotary part of the drive is an important circumstance that leads to increased noise during operation of the drive and a decrease in its kinematic accuracy. Dynamic modeling shows that reducing the imbalance of rotary drive systems is an effective tool for improving its dynamic quality. Reducing the imbalance of the rotating parts of the drive is achieved by increasing the accuracy of their manufacture, followed by dynamic balancing.

Keywords: metal-cutting machine, oscillations, self-oscillations, parametric oscillations, drive, unbalance, unbalance of rotary systems, resonant modes.