Key Engineering Materials Vol. 685

Abstract: Diagnostics of mechanisms and systems allows estimating their current state and taking measures if necessary to carry out preventive or other actions for elimination of possible malfunctions. Diagnostics of mechanical parts of combustion engines, as well as other mechanical devices, mechanisms and systems as a whole, is the relevant objective. The purpose of the paper is to research the possible use of time-frequency autocorrelated function to analyze the combustion engine vibration signals to determine possible defects in its work. The paper introduces the basic possible definition of engine operation processes characteristics, being accompanied by emergence of additional frequency components in a spectrum of engine vibrosignal. The time-frequency correlation analysis allows receiving out of spectrum of engine vibrosignal additional information on weak periodic signals characterizing existence of any malfunctions of its mechanical part.

Abstract: In the given paper the influence of friction forces in the bearing on the accuracy of automatic balancing unbalanced rotors by pendular automatic balance devices is considered. Magnitude of residual offset of a rotor–pendulums system depending on the friction forces is received, that allows defining residual vibration of the mechanism.

Abstract: A brief analysis of the capabilities of the methodological evaluation of foundry technologies effectiveness is presented by the example of temperature condition adjustment of foundry procedure. It has been revealed that the methodological analysis as applied to different variants of foundry technologies allows determining the most effective ways of development of the foundry technology and increase in its efficiency. A reference to various examples shows the presence of the hidden reserves in foundry technologies. The authors conclude that the methodological analysis allows effective and timely adjustment in the development and modification of foundry technologies and enhancement of its effectiveness. The result of the conducted methodological evaluation is elaboration of the guidelines on the enhancement of foundry technologies effectiveness, aimed at the search of the hidden reserves of already functioning technologies.

Abstract: The paper presents the information on the temperature influence on the structure and properties of copper alloys. The results of mechanical testing of samples made of tin-base bronzes depending on the pouring temperature and section thickness of the casting have been discussed. The correlation between the superheat value and distribution of structural constituents of multicomponent tin-base bronzes has been considered. It has been ascertained that the increase in the pouring temperature not only causes grain refinement in eutectoid and lead impurities in tin-base bronzes, but also has a favourable effect on their hydrostrength.

Abstract: The paper is devoted to the analysis of the issues connected with crystallisation of multicomponent bronze during centrifugal casting. Bronze containing tin, lead, zink, nickel, copper has been chosen as a material for study. In the course of the study the spin rate of the mould has been varied. The researches of the structure have shown that during solidification of the cast the quantity of lead increases from the middle part to the inner one, and for high spin rates the difference in lead content in different cross sections of the casting being less noticeable than in case of the low ones. In addition it has been noted that great spin rates of the mould reduce liquating processes and provide a more homogenuous structure of casts.

Abstract: The paper is devoted to the establishment of the technology of castings manufacture out of multicomponent aluminium bronzes for oil and gas producing equipment. Aluminium bronze containing iron has been chosen as a material for casting manufacture. Founding into sand mixtures has been chosen as a manufacturing method. It has been shown that this type of founding allows obtaining the castings with minimal subsequent treatment and high quality surface. The use of the coke furnace at metal melting allows obtaining the castings with high performance characteristics due to gas protection of the melt.

Abstract: Statistical methods are widely used at quality control of products and services. One of the main tasks of quality control with the help of statistical methods is control plan development. Planning control is a difficult task. In this connection, the present article offers an automation of planning control with a grapho-analytical method and a method of operating characteristics.

Abstract: The work presents a thermodynamic study of the influence of doping elements on diffusion saturation of the surface of ZhS6U nickel heat-proof alloy in activated gas media. The paper analyses initial gas media (activators) and their influence on the process of circular chrome-aluminizing.

Abstract: The work presents a thermodynamic analysis assessing the formation of aluminum and chrome halides for diffusion chrome-aluminizing of the surface of nickel heat-proof alloys in activated gases. The author has established chemical reactions that are responsible for the process of circular chrome-aluminizing and the arrangement scheme of initial technological components.

Abstract: The given paper presents the flowchart of the worked out SLS print setup. The setup consists of a laser source, a reactor tube, a laser sweeping system (scanatory system), a control unit, a gas supply and pumping-out system, a melting process visual review system. The paper covers the results of the given setup operation, introduces a sample made with the use of SLS printing and some of its parameters.