Articles

 


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1.
dx.doi.org/ 10.18577/2307-6046-2018-0-9-3-11
УДК 669.187.56:669.14
Krylov S.А., Makarov А.А., Tonysheva О.А., A.N. Mosolov
INVESTIGATIONS OF THE INFLUENCE OF QUALITY OF THE CONSUMED ELECTRODE ON THE PROCESS OF ELECTROSLAG REMELTING UNDER PRESSURE OF HIGH-NITROGEN STEELS

The process of electroslag remelting under pressure (PESR), as well as classical electroslag remelting (ESR), provides refining of the remelted metal. However, the fundamental difference between PESR for the creation of high-nitrogen steels with super-equilibrium nitrogen content is alloying of steel with nitrogen in the process of remelting with nitrogen-containing ligatures (silicon nitride, nitrated ferrochrome, manganese nitrided). Depending on the class of steels, the amount of nitrogen absorbed during remelting can be up to 1% by weight. Partially, nitrogen can be introduced when smelting the consumable electrode, but its solubility without creating excess pressure is severely limited. Increase the solubility of nitrogen in steels is possible with the help of an excess pressure of nitrogen gas above the melt and subsequent crystallization of the ingot. Thus the quality of the ingot-PESR (presence or absence of metallurgical defects) depends on the initial billet – a consumable electrode, which is directly related to the quality of the technological process and remelting change modes. One of the criteria for the quality of the consumable electrode is the presence of pores, their dimensions, and the total volume fraction. It was established experimentally that introduction of nitrogen in the melting in vacuum furnaces, providing a tight consumable electrode can be ignored, and the parameters affecting the stability modes when PESR: pore size of the gas should not exceed 500 microns, and their volume fraction – less than 0.25%. The coefficients of nitrogen doping of consumable electrodes during smelting are determined, which ensure that there is no coarse gas porosity – 0.5≤K≤0.8. The requirements imposed on the consumable electrode: chemical composition of the electrode should provide the chemical composition of the steel after PESR with the input of the alloying elements; the consumable electrode must prov

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2.
dx.doi.org/ 10.18577/2307-6046-2018-0-9-12-20
УДК 669.018.44:669.245
Stoyakina E.A., Simonov V.N., Alekseeva M.S.
RESEARCH THE PROBLEMS OF FILTRATION OF A HIGH-TEMPERATURE NICKEL ALLOY ZhS32 AGAINST AN IMPURITY OF SILICON

This article is a research paper. The article studies the process of filtration of a high- temperature nickel alloy against harmful impurities: sulfur, silicon, phosphorus, oxygen; as well as the possibility of refining high-temperature nickel alloys by adding yttrium has been studied.

The article consists of four parts.

The introduction refers to the use of high-temperature nickel alloys as parts of jet and turbojets, examples of the use of blades for engines made of heat-resistant nickel alloys, as well as their advantages. The influence of impurities on the properties of high-temperature nickel alloys is described. The process of filtration of the ZhS36 alloy by the addition of lanthanum is considered, the effect of variable sulfur content on the durability of the material is given.

In the methodological part, the chemical composition of the alloy under investigation is presented, the used motods for making samples of a high-temperature nickel alloy and a yttrium- based specimen are described, the methods of investigation with a scanning electron microscope and an X-ray diffractometer.

In the main part of the article the results of investigations are presented, microstructures of two samples of a high-temperature nickel alloy ZhS32 with different silicon content are described, a local elemental composition is made, as a result of which it is established that the impurities are mainly located near and in the pores of the material. The microstructure and elemental composition of the master alloy sample based on the yttrium compound with silicon Y5Si3 was also studied. As a result of the X-ray diffraction study, it was established that the master alloy sample contains 5 phases, three of which contain silicon. It is established that these phases are not refractory.

The final part of the article contains the mai

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3.
dx.doi.org/ 10.18577/2307-6046-2018-0-9-21-31
УДК 678.8
Dushin M.I., Donetskiy K.I., Timoshkov P.N., Karavaev R.Y.
RESEARCH OF PROCESS OF OUT-OF-AUTOCLAVE FORMATION SEMI-PREGS ON THE BASIS OF CARBON FILLERS (rеview)

The increase in let-out volumes and especially dimensions оf products from composite, has demanded search of cheaper alternatives to avtoklave way of manufacturing of products. Ways of liquid vacuum formation dry preformеs impregnation binding have appeared the cheapest. The arisen problems of receiving high-quality products vacuum formation have led to development semi-pregs, representing fabrics or cordlike fillers which are duplicated with film of the binding. Many manufacturing firms of materials include in the nomenclature of the materials wide ruler semi-pregs. In work researches of processes of receiving polymeric composite materials (PСM) on the basis of developed semi-pregs by means of their formation by means of atmospheric pressure instead of autoclave for manufacturing of load bearing structures are considered. The interrelation of porosity of plastics, permeability, and some other parameters for the purpose of receiving PCM with minimal porosity and properties, approximate to avtoklave formation is investigated PСM.

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4.
dx.doi.org/ 10.18577/2307-6046-2018-0-9-32-42
УДК 669.721.5
Kozlov I.A., Vinogradov S.S., Uridiya Z.P., Duyunova V.A., Manchenko V.A.
EFFECT OF PRELIMINARY ETCHING OF ALLOY ML5 BEFORE PLASMA ELECTROLYTIC OXIDATION

At process research PEO on alloy of ML5 it has become clear that on properties of covering the great influence renders alloy surface condition. Research cross sample ML5 alloy with PEO the covering received on different sites of sample, having phase Mg17Al12 and phase AlхMnу inclusions, has shown that close aluminum - containing phase is created the covering, having serious defects and through time.

This phenomenon speaks that at early stage of process of PEO the tight barrier oxide layer on aluminum - the containing phases Mg17Al12 and AlхMnу is created smaller thickness and with smaller electroresistance. Upon transition to the following stage of process of PEO being formed as a result of oxide layer breakdown microplasma discharges are localized on energetically favorable places of covering what sites with smaller electroresistance of barrier oxide layer, that is on the phases Mg17Al12 and AlхMnу are. The increase in quantity of microplasma discharges in one place leads to strong warming up of oxide layer that in turn leads to its escalating destruction and formation of through defect on the phases Mg17Al12 and AlхMnу and in adjacent areas. Localization of microplasma discharges on the phases Mg17Al12, AlхMnу and near them in the course of PEO leads to the selection oxidation of surface and formation of volume defects of PEO of covering.

For decrease in deficiency preliminary chemical treatment of the magnesium alloy, allowing to exclude electrochemical heterogeneity of surface of alloy at the expense of etching of phases or formation of insulation layer is offered.

The conducted electrochemical researches&

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5.
dx.doi.org/ 10.18577/2307-6046-2018-0-9-43-50
УДК 621.794.61
Dyomin S.A., Vinogradov S.S.
REPAIR OF CHEMICAL OXIDE COATING ON CARBON STEEL

One of widely applied protecting coatings especially in the conditions of contact with oils and fuel is the chemical oxide coating put on such details, as gear wheels, toothed wheels, axes, plugs, rods, rods, etc. The chemical oxide coating on carbon steel represents the thin film which is easily destroyed at mechanical influences. The purpose of work was development of technology of local repair of chemical oxide coating on carbon steel with use of the solution which is not containing substances of the 1st class of danger, and without necessity of its heating.

Researches of protective properties of the films received as a result of processing of steel details in oxalic solutions, containing persulfaty, tiosulfaty and sulfites (fig. 1), in solution of the tannin with addition of phosphoric acid, and also in the acidified solutions of oxidizers (permanganate, nitrite, nitrate, tungstate and vanadate of alkali metal) are conducted. Tests of the received films by drop method (solution of copper sulfate of 20 g/l) have not allowed to recommend any of the studied solutions for repair of chemical oxide coating: time before emergence of contact copper on surface there were no more than 20 с (tab. 1-5).

The film of satisfactory quality has been received at the cathode surface treatment of carbon steel by rubbing method by marker with molibdenum solution. Detail with the damaged covering connected to negative pole of source of current, the free end of the corrosion-proof wire fixed in marker, – to positive pole of source of current. At the current density of 5-10 A/sq.dm the film of black color (fig. 2) with protective ability more than 40 с (tab. 6) that above protective ability of chemical oxide coating is formed.

Simplicity of hardware registration of process and availability of chemicals along with positive results of resear

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6.
dx.doi.org/ 10.18577/2307-6046-2018-0-9-51-60
УДК 620.178.35
Gorbovets M.A., Khodinev I.A., Ryzhkov P.V.
EQUIPMENT FOR TESTING CARRYING OUT THE STRAIN-CONTROLLED LOW-CYCLE FATIGUE

The use of modern materials in the design of aircraft gas turbine engines (AGTE) is possible only if the material has undergone a variety of strength tests. The types and scope of the tests are established by normative and technical documentation. When evaluating the strength of materials, their resistance to fatigue loading is of great importance. The following characteristics of fatigue are to be assessed: the resistance of high- and low-cycle fatigue (HCF and LCF), as well as the fatigue crack growth rate (FCGR). For heat-resistant steels and alloys used in the AGTE design, these characteristics are determined at various temperatures of the operating interval.

When carrying out mechanical tests, three factors determine the decisive influence on the determined characteristics: the accuracy of the testing machine, the technology of sample production, in particular, the quality of the surface layer, as well as the properties of the material being studied. The influence of the first two factors is discussed in detail in this article.

To carry out a variety of fatigue tests, universal servo-hydraulic testing machines of the LFV-100 type of the Swiss company Walter+bai with high rigidity of construction are used. They are a two-column structure that can be equipped with different grips and represents the possibility of carrying out all the fatigue tests mentioned above. The machine provides high alignment in the loading (deformation) circuit of the samples, which is a very important positive characteristic, as well as the possibility of cyclic testing of samples of metals and alloys in the temperature range from room temperature to 1200°C. The control of the testing process is carried out with specialized computer programs that enable the conduct of mechanical research.

LCF is one of the main characteristics of strength for&

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7.
dx.doi.org/ 10.18577/2307-6046-2018-0-9-61-70
УДК 620.1
Oreshko E.I., Erasov V.S., Kachan D.V., Lashov O.A.
RESEARCHES OF STABILITY OF CORES AND PLATES AT COMPRESSION WITH THE JAMMED CROSS-SECTION EDGES

Tests for loss of stability of samples from an alloy 1441 with various speeds of deformation which did not show dependence of critical force of loss of stability on speed of loading of a sample are carried out.

Calculations on loss of stability of homogeneous plates of constant thickness with the jammed cross-section edges are executed. Calculation of critical efforts is executed analytically on formulas and a method of final elements on the basis of bifurcate statement of a task with use of the program ANSYS Mechanical APDL complex.

At comparison of experimental data with the results received on a formula for calculation of stability of plates, the difference with calculation was in the range of 25–37%. At comparison with Euler's formula results of experiment differed from settlement for 18–30%.

The divergence in settlement and experimental values of critical force of loss of stability of samples speaks in sensitivity of this characteristic to geometry of a sample which always has some initial curvature.

Values of critical force of loss of stability of the plates, received by a method of final elements in the program ANSYS complex, exceed the values received on a formula of Euler for cores, but it is less than results of calculations on a formula for plates.

Without Puasson's factor results of numerical calculations of MKE correspond to the results received on a formula of Euler. With increase in factor of Puasson difference of results numerical and analytical calculations raises.

Change of thickness of a plate and the module of elasticity does not influence an error of calculations of MKE of rather analytical results.

Extent of coincidence of results of calculations&

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8.
dx.doi.org/ 10.18577/2307-6046-2018-0-9-71-82
УДК 678:620.193.21
Slavin A.V., O.V. Startsev
PROPERTIES OF AIRCRAFT GLASS- AND CARBONFIBERS REINFORCED PLASTICS AT THE EARLY STAGE OF NATURAL WEATHERING

Novel carbon fiber reinforced plastics VKU-27l, VKU-39, VKU-46 and glass reinforced plastics VPS-47/7781, VPS-48/7781, based on VST-1208, VSE-1212, VSR-3M resigns in initial state and after 12 month of weathering in warm and mild cold climate were investigated by means of profilometry, diffusion analysis and dynamical mechanical analysis. The influence of material composition on mean size of sample surface inhomogeneities, moisture content, diffusion coefficient, glass transition temperature of resigns was studied. The physicomechanical transitions were studied at the early stage of natural weathering.

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9.
dx.doi.org/ 10.18577/2307-6046-2018-0-9-83-91
УДК 620.177
Avtaev V.V., Kotova E.A., Gladkikh A.V., Boychuk A.S.
EQUIPMENT FOR BENDING TESTS CONSTRUCTIVE AND SIMILAR SAMPLES WELDED HYBRID PANELS OF THE WING

The article describes the various methods of static loading constructive-like specimen of a hybrid welded wing-skin panel for determining of strength characteristics. It is determined that selection of optimal loading method is influenced by the necessity of structure element resistance force determination or zone hybrid elements, the shear stress level in the design, test equipment and test complexity possible. It is shown that for the hybrid and welded panel zone investigation, including the quality and stability bonding technology determination, is preferred by bending loading scheme.

Testing equipment is proposed in the form of two identical supports and a loading tip with rounded contact surfaces for three-point bending test of constructive-like specimen of a hybrid welded wing-skin panel with longitudinal stringers. Using the developed equipment allows bending loading for constructive-like specimen of a hybrid welded wing-skin panel both along the stringer and across. The sustainability of the constructive-like specimen hybrid wing-skin panels in three-point bending test using proposed testing equipment is provided by fixing the stringers and preventing the local crumpling and brittle fracture of the hybrid laminate strips during the test by reducing the contact stresses.

To proofing testing equipment, for bending test of constructive-like specimen of a hybrid welded wing-skin panel with longitudinal stringers and welded joint (friction stir welding technology), located along the stringer made of the extruded V-1469-T1 alloy profile, with reinforcing hybrid laminate strips (GRP based on hot-melt adhesive prepreg KMKS-2m.120-T64 and carbon fibre-reinforced plastic VKU-30K.R14535) were carried out in Gelendzik climatic testing center (GCTC). Its operability checked after the tests, according to the results that the local destru

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10.
dx.doi.org/ 10.18577/2307-6046-2018-0-9-92-104
УДК 620.1
Erasov V.S., Avtaev V.V., Oreshko E.I., Yakovlev N.O.
STRAIN-CONTROLLED TESTING ADVANTAGES AT STATIC TENSION AND REPEATED-STATIC TENSION

The article presents advantages strain-controlled testing over force-controlled testing at static tension and repeated-static (fatigue) with a fixed deformation step. In addition to the traditional mechanical properties of materials (elastic modulus E, yield strength σ0,2, tensile strength σв, permanent deformation δ), obtained from the stress-strain diagram at tensile test, introduction of additional characteristics (plastic deformation rate , material damage function of the specimen ω, damage velocity ) subject to stress-strain diagram with strain-controlled testing is suggested. The stress-strain diagram relationship with the envelope of the line when the strain-controlled repeated-static testing with a fixed deformation step introduced. Approaches to determining fatigue characteristics using test data in this manner at fatigue testing are showing. For 1441-T1 and 1163-ATB alloys under repeated-static testing, a characteristic effect is observe. A plastic deformation in a certain deformation range is realize discretely at the same stresses (similar to the yield plateau during tension). For alloy B-1481-T1, there is no similar effect.

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11.
dx.doi.org/ 10.18577/2307-6046-2018-0-9-105-118
УДК 620.193
Kutyrev A.E., Chesnokov D.V., Antipov V.V., Vdovin A.I.
THE DEVELOPMENT OF A SOLUTION FOR PROMOTION OF CORROSION ATTACK ON ALUMINIUM ALLOYS IN A GALVANOSTATIC MODE

The aim of research was to derive an electrolyte that could be used to obtain aluminum alloys corrosion damage, identical to one found in natural environments, by anodic dissolution. To determine the right choice of solution pitting corrosion factor was used. Pitting corrosion factor is the ratio of maximum pitting depth to the corrosion depth, derived from specific mass loss under the assumption of uniform dissolution. The power law relationship between specific mass loss and pitting corrosion factor was revealed: pitting corrosion factor is reduced when specific mass loss is increased. It is shown that anodic dissolution in a solution, containing nitrates, sulfites and chlorides, is resulting in corrosion damage with the same pitting corrosion factor as during the natural exposure. This solution can be used to imitate pitting corrosion on aluminum alloys in natural environments. However, in this solution the intergranular and/or exfoliation corrosion is not obtained. Two possible ways to achieve these types of corrosion were introduced: 1) increasing the chloride ions concentration, which reduces the pitting corrosion factor; 2) multistep anodic dissolution in solution, containing nitrates, sulfites and chlorides, first and then in sulfite-chloride solution in order to obtain intergranular and/or exfoliation corrosion. However, both of the approaches require further development of anodic dissolutions regimes and, therefore, further investigations.

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12.
dx.doi.org/ 10.18577/2307-6046-2018-0-9-119-123
УДК 678.6
Chen Yangyang, Marachovskiy P.C., Malysheva G.V.
DETERMINATION OF THERMOPHYSICAL PROPERTIES OF EPOXY MATERIALS DURING THEIR CURING

During the curing of any thermosetting polymer, a consistent change in its phase state takes place and it initially passes from the liquid state to the gel-like and further into the solid state. As an object of research, an epoxy formulation based on epoxy-diane resin and modified aliphatic polyamine was used. In the technical literature, the values of the thermophysical characteristics of epoxy (and other thermosetting) materials are given only in a solid aggregate state, i.e. even after curing, however, these characteristics undergo significant changes in the transition from one phase state to another.

The technique of carrying out thermophysical measurements directly during the curing process is described. A distinctive feature of these tests was the use of a sample in the liquid state, which did not allow to withstand the required geometric dimensions, as well as its optical transparency. A special mandrel consisting of a crucible and a cover made of a platinum-rhodium alloy (its density, thermophysical properties, as well as all the geometric characteristics of the crucible and the cap are known) was used to fill the initial sample and subsequent tests. The test material was placed in the space between the bottom of the crucible and the lid. During the tests, the effective thermal diffusivity was measured, the crucible-test material-cover system was measured. The measurements were carried out over the course of a day, sequentially determining the heat capacity, thermal diffusivity, and thermal conductivity.

As a result of the conducted studies, it was found that during the curing process (i.e., when the degree of conversion is changed), the heat capacity decreases by 32%. Conversely, the values of thermal conductivity during curing, with a similar change in the degree of cure, increase from 0.08 to 0.25 W / (m/K), i.e. more than 3 times. Even more important

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