Nikita V. Martyushev

The Resource Efficiency Assessment Technique for the Foundry Production

The short analysis of the assessment opportunities is presented for the resource efficiency in various industries and particularly in the foundry production. The developed algorithm of carrying out such assessment is presented. It is shown that such algorithm consists of five steps. They are the formation of the evaluating team, the choice of the technology or a product, the analysis of the chain creation of the added value for a technology or a product, the assessment of the current state of the technology or a product, developing the recommendations for the improvement of the efficiency of resources use. This article describes in detail the works, which need to be carried out at each stage of evaluating the resource efficiency. The evaluating map and the criteria are developed for comparing different types of the foundry technologies as well as the map for assessing the current state of the foundry technology. The result of the accomplished assessment with the described algorithm is the developed recommendations on the use of the enterprise resources.

The Possibility of Casting Surface Alloying by Nanopowders

The literature about the mold plastering casting structures applied in alloying the casting coating by various alloys was examined. On the basis of the examined literature the main conditions are revealed, which should be observed for the implementation of the alloying process. The data on plastering structures used for the casting molds with various heat conductivity is presented. The influence of such alloying on the structure and property both of the casting surface and the properties of the finished products is shown. The data on a classical set of covering components and on the features of the elements comprising them is also provided. The conditions necessary for the casting surface alloying by the nanopowder of the casting mold covering are described. A number of cases is described when such alloying was applied and was successful. The changes of the casting surface properties are described.

An investigation into autobalancing devices with multireservoir system

Behaviour of a liquid-type automatic balancing device is modeled in this paper. To perform mathematical research the authors use a rotor model which contains a ring functioning as a reservoir coupled to a rigid shaft being rotatable in bearings. An autobalancer with several reservoirs is used for the mathematical investigation. The article provides the layout of forces acting in a multi-reservoir balancing system. Data on the effect of various factors on balancing accuracy as well as the main calculation features of a multi-reservoir autobalancer are presented. The obtained modeling results indicate that autobalancing efficiency is enhanced by increasing the number of reservoirs. An increase in the number of reservoirs causes a decrease in a critical rotor speed.

Effects of Crystallization Conditions on Lead Tin Bronze Properties

Research results of cooling speed influence on structure and properties lead tin bronze are given in this article. Cooling speed changed by casting mold heating to various temperatures. Following the researches results it is shown that cooling speed growth leads to growth of hardness, strength on samples stretching. Decrease in cooling speed gives decrease in hardness and strength on stretching, but at the same time the impact strength of samples increases. Results of metalgraphic researches showed that such properties changes are connected with phase structure change of cast samples.

Microstructure and Properties of the Composite on the Basis of Copper and Diamond

The paper presents the experimental material on obtaining and researching of three-dimensional composite heat-conducting copper-diamond materials in the system of spark plasma sintering. Earlier [1-5], it was established that in order to achieve the effect of the increased heat conductivity of a composite it is necessary to create the conditions hindering the movement of heat flux on the interface boundary. In this work we have attempted to obtain the material with heat conductivity higher than that of pure copper due to addition of diamond powder and synthesis of the composite in the system of spark plasma sintering. For comparison, we have considered copper and diamond compositions in the ratios of 50/50 and 40/60 correspondingly. The results of the heat conductivity analysis have not exceeded the indices of pure copper; however, according to SEM data, it has been found that at SPS-sintering local domains with enhanced adhesion form on the surfaces of diamonds.

Numerical Simulation of Temperature Field in Steel under Action of Electron Beam Heating Source

It is impossible to improve the most critical performance properties of machine parts without methods of modifying the surface layer using such concentrated energy as laser, plasma, an electron beam or high-frequency currents. For the rational use of these methods, which are characterized by high heating rates, i.e. about 104 ... 105oC/sec a reliable mechanism for determining the processing modes that ensure the required level of quality characteristics of the hardened surface layer of machine parts, is essential. In this paper, the interrelation between the parameter values of thermal cycles, implemented in the surface layer of steel U8, and the modes of electron beam heating in the atmosphere has been determined.

Formation of high-carbon abrasion-resistant surface layers when high-energy heating by high-frequency currents

The paper shows the possibility of carburization of low-carbon steel surface layers using high-frequency currents. The mathematical modeling of carburization using high-energy heating by high-frequency currents (HEH HFC) has been carried out, the temperature fields formed during the given processing have been calculated, as well as the structural changes in the surface layers have been simulated. The features of the structure formation in the surface layers of low-carbon steel after carburizing via HEH HFC have been determined by optical and scanning microscopy, which is confirmed by the computational models. The rational mode of fusion via HEH HFC has also been determined (power density of the source qs = (1.5 ... 4.0) • 108 W m-2, (the relative travel speed of parts Vp = 5 ... 100 mm / sec), with forming the compressive retained stresses in the surface layer (σRS ≈ -300 ... -400 MPa).

The features of steel surface hardening with high energy heating by high frequency currents and shower cooling

The paper examines the process of surface hardening of steel 45 with the help of high energy heating by high frequency currents with simultaneous shower water cooling. We theoretically justified and experimentally proved a possibility of liquid phase forming in the course of heating not on the surface, but in the depth of the surface layer.

Integrated Quality Ensuring Technique of Plasma Wear Resistant Coatings

We propose the technique of guaranteed quality wear resistant plasma coatings of high-chromium powder material. The appropriate system of engineering models had to be designed in order to obtain the summarized results, as well as to manage the parameters of quality indicators at all stages of the technological processing procedure. Thus, surface roughness was accepted as a criterion in the model development at the stage of preliminary mechanical processing before spraying coatings. The model of plasma coating process proper takes into account the influence of spraying on the main quality indicators, such as adhesive strength, porosity, and the level of residual stresses. The engineering model of finish abrasive grinding is based on ensuring the desired value of the surface roughness parameter provided the geometric and dimensional accuracy of details was achieved.

The method of quantitative automatic metallographic analysis

A brief analysis of the existing softwares for computer processing of microstructure photographs is presented. The descriptions of the the software package developed by the author are demonstrated. This software product is intended for quantitative metallographic analysis of digital photographs of the microstructure of materials. It allows calculating the volume fraction and the average size of particles of the structure by several hundred secants (depending on the photographs resolution) in one vision field. Besides, a special module is built in the software allowing assessing the degree of deviation of the shape of different particles and impurities from the spherical one. The article presents the main algorithms, used during the creation of the software product, and formulae according to which the software calculates the parameters of the microstructure. It is shown that the reliability of calculations depends on the quality of preparation of the microstructure.