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scientific edition of Bauman MSTU

SCIENCE & EDUCATION

Bauman Moscow State Technical University.   El № FS 77 - 48211.   ISSN 1994-0408

Constructional Material Processing in Machine Building

Anticorrosive processing of low-carbonaceous steel by pulsed plasma flows
# 12, December 2013
DOI: 10.7463/1213.0670510
A.S. Kamrukov, E.I. Denisov, N.P. Kozlov, E.A. Lushnikov
Development of new progressive technologies for improving corrosion resistance of construction materials is a crucial scientific and technical task which could be solved efficiently by modification of various plasma methods. This work considers a possibility of obtaining the corrosion-resisting effect by modifying physical and chemical properties of constructive materials’ surfaces during processing with high enthalpy pulsed plasma flows. A pulsed technological plasma burner based on a high-current discharge magnetoplasma compressor in the atmosphere was developed. Results of an experimental research of energetic, thermodynamic and temporal characteristics of the impact of pulsed plasma flows on construction materials were presented: the temperature of the plasma flow was 13000 …15000K, of the plasma pressure – 70…390 bar, radiation flux density was up to 300 kW/cm2, energy density of the plasma exposure was 10... 40 J/cm2, a typical exposure time was 65 ... 125 ms. Irradiation experiments with pulsed plasma flows made of samples of St3 steel were performed. Evaluation of corrosion properties of plasma-modified surfaces was carried out. A significant increase in corrosion resistance of surfaces of structural carbon steels modified by such kind of treatment was demonstrated using the method of accelerated tests.
A heat mathematical model of polymer composite cylinder during microwave treatment
# 01, January 2014
DOI: 10.7463/0114.0658448
УДК: 629.782: 621.763
S.V. Reznik, S.A. Rumyancev
Traditional technologies of producing epoxy based polymer composite materials (PCM) require a long-term and energy consuming thermal processing. Microwave heating could be used as an alternative technology for heating work pieces made of PCM; this would allow one to reduce treatment time and energy consumption significantly. A mathematical model of temperature distribution inside the cylindrical composite system during microwave treatment was investigated in this paper. The model includes hollow PCM cylinder made of epoxy binder and carbon fibers and solid cylindrical mandrel. Theoretical and experimental results on the temperature state of the system were analyzed and discussed.
Selection of a metal-cutting machine model: a formalized approach
# 12, December 2013
DOI: 10.7463/1213.0640867
G.P. Lazarenro
The article covers formalisation of procedures of selecting technical equipment tools during the design of technological processes. A general analysis of the problem was carried out; it was approbated on a practical task of machine selection. The problem was solved by a standard two-stage scheme: 1 – selection of potentially suitable models of machine; 2 - selection of the most preferred model. The methodology of comparative analysis of numerical and linguistic vectors was applied as a tool for formalising the solving procedure of this task along with the methodology of multi-criteria optimisation of choice. The obtained results confirmed the possibility of practical solving of this problem based on application of the mechanisms of the quantitative analysis and the procedures described by formal algorithms.
Estimating efficiency of interrupted cutting on the basis of change pattern in heat density of the process
# 10, October 2013
DOI: 10.7463/1013.0623113
V.M. Yaroslavtsev, N.G. Nazarov
Calculation models of changes in heat density of an interrupted cutting process and their connection with technical and economical processing indexes were considered in this paper; these indexes allow one to determine changes in cutting tool life and in working efficiency, depending on kinematical features of the process. Manufacturing operation and kinds of work such as edge cutting, abrasive and surface plastic deformation with cyclic change of mode parameters were presented. During investigation of these operations or their development at the stage of process design it is rational to apply the specified models.
Electrochemical modification of surface properties of carbon fiber based on the polyacrilonitrile
# 09, September 2013
DOI: 10.7463/0913.0620998
I.S. Strahov, A.A. Gubanov, M.S. Ustinova, D.I. Krivcov, V.Ya. Varshavskii, T.A. Vagramyan, I.V. Plyuschii, Yu.V. Korshak
Electrochemical and subsequent chemical treatments of carbon fiber produced by two-stage thermal stabilization and carbonization of polyacrylonitrile fiber were used for modification of its surface to improve its adhesive properties with epoxy matrix. Electrochemical treatment initiates complicated physical and chemical transformations which lead to etching, lengthwise channels and cross-link formations between carbon filaments. Various conditions for electrochemical treatment of carbon fiber in water solutions of ammonium salts (NH4)HCO3/(NH4)2C2O4 were used to determine the optimal modes and to increase the tensile strength value of microplastics up to 10% compared to untreated carbon fiber samples. Coating the surface of carbon fiber with polymer layers by electrochemical polymerization was applied; this approach appeared to be an alternative and effective way for modification of surface properties.
Increasing efficiency of flat grinding by cup wheel’s end face on the basis of control of the heat-stressed state of a working zone
# 09, September 2013
DOI: 10.7463/0913.0606036
T.N. Ivanova
Flat grinding by cup wheel’s end face usually is more efficient than other types of grinding because many abrasive grains simultaneously take part in the process; this leads to the decrease in machined surface roughness. At the same time, due to a large area and duration time of contact between the face wheel and the detail, this particular type of grinding is characterized by high heat release rate. In order to achieve the required quality face grinding is usually conducted at reduced power. That is why determination of relations and patterns in the process of face grinding of flat surfaces, which influence the heat-stressed state of the working zone would allow to increase machining efficiency of flat details.
Experimental determination of drilling cutting forces based on dimensional analysis and the similarity theory
# 09, September 2013
DOI: 10.7463/0913.0598978
A.M. Guskov
This paper deals with the similarity theory and dimensional analysis for investigating cutting forces – particularly during drilling. Use of dimensionless groups allows one to obtain relations which are independent of unit systems, reduce the number of significant variables; it also helps to avoid influence of measurement bias on the dimension of physical relationships and ensure comparability of experimental results obtained under various conditions by different authors. Eleven dimensionless quantities for cutting process characteristics were proposed. Based on the experimental data for 3 types of drills, polynomial and power cutting laws for both axial force and torque were derived. Extension of those relationships to the case of vibrational drilling was considered; a method of applying existing relationships to obtaining of cutting laws in the form of dimensionless criteria was proposed.
Process analysis, sharpening and testing of cutters made of boron nitride
# 09, September 2013
DOI: 10.7463/0913.0598355
S.V. Grubyy, V.V. Lapshin
In this paper the authors consider a process of finish turning of work pieces made of hardened steel with cutters equipped with tool materials based on boron nitride such as cubic boron nitride CBN10 (SECO) and Dense Boron Nitride (DBN). An analysis was conducted, and a method for calculating parameters of turning hardened steel work pieces was proposed; these parameters are forces, cutting temperature, wear rate, magnitude of wear, tool durability and parameters of chip formation. In the experimental part of this study the authors describe a technology of precision sharpening of cutting tools made of DBN; the quality of sharpening was estimated. Test results of the cutters during the process of turning of cylindrical and end face surfaces along with boring a hole in a work piece made of 9HS HRC 60 steel are presented in this work. Results of a quality estimation of the machined surfaces are also given. The conducted studies confirmed effectiveness of the use of cutters made of dense boron nitride for precision machining of hardened steel.
The purpose of geometrical parameters of the tap’s cutting part during processing of non-continuous surfaces
# 09, September 2013
DOI: 10.7463/0913.0590761
A.E. Dreval', I.V. Ivanina
In this article the authors consider an analytical form of the pattern change in the total radial force in forming discontinuous threaded surfaces by using the generator cutting scheme (taps, dies, die heads, etc.). A modeling method for various configurations of surfaces for threading was proposed. The authors propose an engineering technique of design decision-making for tool’s working elements and of the purpose of geometrical parameters of the tap’s cutting part during processing of non-continuous surfaces. The possibility of eliminating agreement between peak load on the cutting tooth and the moment of its interaction with a non-continuous surface was investigated.
A study of lathing characteristics on the basis of obtaining and analyzing multidimensional polynomial dependences
# 08, August 2013
DOI: 10.7463/0813.0589299
L.D. Mal'kova, M.A. Chihareva
This article considers a possibility and an algorithm of the mathematical study of polynomial dependences which are used for describing characteristics of machining. The authors describe advantages of polynomial dependences obtained on the basis of a complete factorial experiment in multidimensional parameters spaces. For illustrative purposes, an analysis of energy consumption during two-stage lathing was carried out on the basis of the obtained polynomial dependence of the tangential cutting force on processing factors. The influence of the specified factors was established a priori on the basis of conducted experimental studies or literary sources. Conditions and results of all the conducted experiments are presented in this paper along with the algorithm for determining the minimal value of energy consumption.
Practicability of purchasing new metal-cutting machinery
# 08, August 2013
DOI: 10.7463/0813.0587093
D.V. Vinogradov
An approach to decision making on practicability of purchasing new metal-cutting machinery in the context of processing’s prime cost was proposed; this is an actual problem for many machine builders which upgrade their machine tool population. It was shown that the cutting speed that provides minimal prime cost is a key to this problem. A formula for estimating the lowest prime cost of cutting action was derived. The author analyzed key factors influencing the solution to the problem of practicability of purchasing a new metal-cutting tool. It was also shown that it is impossible to reduce the prime cost of processing by increasing cutting speed. The only way to reduce the prime cost of processing by new equipment is a decrease in auxiliary time. The area of unprofitability of old machinery replacement was determined.
Investigating the influence of cutting conditions on wear of thread cutters with an internal chip-carrying
# 08, August 2013
DOI: 10.7463/0813.0583417
A.V. Litvinenko
This article provides results of investigations aimed at reasoning of the increase in the working capacity of a new type of thread cutters with an internal chip-carrying. Determination of the wear criterion, which characterizes the admissible wear limit, is an important stage for estimating the working capacity of the thread cutter. This criterion, in general, depends on the kind of failure, cutting conditions, tool and work materials, structural and geometric parameters.
Influence of pressure on supporting surfaces of the cutting profile on the accuracy of the thread being cut
# 08, August 2013
DOI: 10.7463/0813.0590745
I.V. Ivanina
The author developed a mathematical model that sets basic laws of changes in specific forces in formation of the thread surface and allows one to determine priorities of technical activities aimed at improvement of accuracy and stability of the process of threading. Pressure diagrams for tap tool minor cutting edges were obtained. This is useful for load distribution analysis between cutting teeth. Results of theoretical and experimental studies on the effect of the cutting angle of the taps on the dynamics and precision of the threading process are presented in this paper. A correlation between the character of overpressure on instrument base surfaces and a classification of thread types was determined.
Pipe couplings for shaft connection
# 07, July 2013
DOI: 10.7463/0713.0577791
D.S. Blinov, V.M. Zyablikov, V.F. Smirnov, A.A. Shirshov, V.F. Alyoshin
Elastic pipe couplings are used in low power drives because their application is limited due to loss of section stability under loading of comparatively low rotational moment. This results in significant performance degradation of properties of such couplings. In order to improve section stability and, therefore, to increase the transfer moment, it was proposed to fill the pipe’s internal space (between shafts to be connected) with narrow metallic rings which were mounted with some tension. Changing the number and height of rings could lead to changes of the coupling properties. A coupling with an elastic metallic assembly mounted in the pipe’s hole was developed for operation under high dynamic loads. A patent for invention of the Russian Federation was received for this coupling.
Cutting tool materials for edge tool manufacturing
# 05, May 2013
DOI: 10.7463/0513.0569432
N.N. Zoubkov
This article is based on the review of Russian and foreign periodicals about edge tools published in the last seven years. Existent up-to-date cutting tool materials for edge tools are presented in this work. Their physical and mechanical properties and rational application areas were also described. Special attention was paid to new types of oxide, mixed, whisker-reinforced and silicon nitride cutting ceramics and extra-hard cutting tool materials based on the poly crystalline diamond and cubic boron nitride. Comparison of Russian and foreign trade marks producing cutting tool materials was presented. Classification of extra-hard diamond-based cutting tool materials was also given. Analysis of development prospects of cutting tool materials was carried out.
Cutting with outrunning plastic deformation in technologies of utilization of metal chips
# 07, July 2013
DOI: 10.7463/0713.0567548
V.M. Yaroslavtsev
The author considers different possibilities of increasing efficiency of processing of metal chips during utilization by means of crushing them with the use of machine-tools while processing work pieces. It was shown that application cutting with outrunning plastic deformation (OPD) during the processing provides both reliable crushing of flow chips and high technological and technical-and-economic parameters of the processing. Cutting with OPD and crushing of metal chips allows to eliminate one of the most time-consuming operations of utilization –  that is granulating with the use of special equipment before briquetting and remelting. Experimental data on durability of toothed elements of crusher rolls that are used for crushing metal chips during the processing with OPD are presented. Recommendations are given on selection of a material for toothed elements and of their geometry, depending on properties of the material to be processed. It was established that application of elements made of hard alloy of VK6, VK6OM allowed them to work without regrinding for more than 20 hours.
Manufacturing capability of hole reaming with outrunning plastic deformation
# 06, June 2013
DOI: 10.7463/0613.0567522
V.M. Yaroslavtsev
Construction of a reamer which implements a combined cutting process with outrunning plastic deformation (OPD) during hole-making operations is considered in this article. The author provides results of an experimental investigation of efficiency of hole reaming with OPD while processing 20H13, I2H18N10T, 10H12N22Т3МR steels and L63 latten. Experience has shown that design features of a reamer appear in stabilization of the cutting process with random disturbances and eliminate vibrations in cross direction, increase homogeneity of the surface layer structure. This leads to decrease in ruggedness of the finished surface, more uniform distribution of this ruggedness over the length of a detail, increase in micro-hardness of the surface layer along with technological durability of a tool and process efficiency.
Increasing plasticity of welded TRIP-steel joints with the use of additional pulse current at resistance spot welding
# 04, April 2013
DOI: 10.7463/0413.0548028
A.A. Terehov
The author considers problems of increasing plasticity of welded TRIP-steel joints at resistance spot welding. Special attention is paid to application of using an additional heat treatment pulse and its parameters. The author investigated the influence of the pause between the basic and secondary pulse currents, as well as the volume of the heat treatment current on mechanical properties of welded joints. The author gives an assessment of the influence of electro heat treatment on micro-hardness parameters and mechanical properties of welded joints; this allows to optimize the pause duration and the volume of the heat treatment current. Practicability of applying the additional pulse current to increase the plasticity of spot welds was proved on the basis of the obtained results.
Influence of a shaped blank on force power characteristics of manufacturing wrapped angular contact metal-fluoroplastic slider bearings
# 03, March 2013
DOI: 10.7463/0313.0544282
A.B. Gospodchikova, A.V. Vlasov
In this article the authors cover improvement of manufacturing metal-fluoroplastic bearings from a parent sheet. The distinct feature of this work is producing a liner with a flange from the parent sheet. The authors revealed a procedure of forming a bearing flange using finite element simulation. Zones of non-uniform deformation were found. These zones can reduce the product quality. It was proposed to change the shaped blank form in order to reduce the zones of non-uniform deformation and relieve the metal flow. Simulation of the deformation process with the use of the new shaped blank demonstrated decrease in energy-power characteristics of the process and increase in uniformity of the deformed condition. The results of the research will help to improve the quality of metal-fluoroplastic bearings used in aviation.
Supports for resisting axial forces in centrifugal mechanisms with heavy rotors
# 04, April 2013
DOI: 10.7463/0413.0543274
D.S. Blinov, V.M. Zyablikov, V.F. Alyoshin
Heavy rotating shafts with radial bearings require an additional axial support. Axial support in some mechanisms is designed poorly. This article describes a developed design of an axial support and results of its structural analysis. This design is patented in the Russian Federation. The proposed support is designed for installation on the free end of the shaft and does not interfere with the shaft’s radial float and rotation of its axis. The admissible lateral displacement of the shaft in the axial installation is 1-2 mm, and the maximum rotation of the shaft axis is 30 arc minutes. The support is suitable for the shaft of an oil turbo pump unit. This shaft is mounted with bearings; its axis has radial and angular displacements during the operation.
 
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