Purpose. Providing deformation conditions in order to obtain the required texture of pipes made of Ti-3Al-2.5V alloy based on the choice of rational values of the tool calibration parameters gauges and mandrels during cold pilger rolling of pipes for the required Q-factor distribution along the deformation cone. Methodology. The research methods were based on the existing dependence, which describes the influence of the distribution of the ratio of true reduction along the deformation cone along the wall thickness and along the average diameter, on the distribution of the Q-factor value. The calculation of calibration and all deformation parameters of the Cold Reducing tube process was based on a number of existing theoretical and empirical dependencies included in the generally accepted and adapted methods of their computation. To perform calculations, we created the software product Q-Factor. Cold pilger tube rolling. Findings. The influence of the initial taper of the mandrel with a curvilinear generatrix and the sweep of the groove ridge, the degrees of steepness of the generatrix of the mandrel and the sweep of the groove ridge, the value of the feed on the distribution of the Q-factor along the compression zones and pre-finishing of the deformation cone were investigated by calculation. The use of slope degrees n, equal to 1.5, i.e. less than values of crest slope degree had the most significant effect on obtaining the Q-factor close to equilibrium distribution along the length of wall reduction and pre-finishing zones. A method of multifactor calibration of the tool for cold pilger rolling of pipes is proposed, which makes it possible to select rational values of the initial taper of the mandrel with a curved generatrix, the degree of slope of the sweep of the groove ridge and the mandrel, and to create conditions in the wall compression zone for obtaining the required type of metal texture of cold-rolled pipes made of titanium alloy Ti-3-2.5V. At the same time, in the prefabrication zone, in all investigated cases, there is a drop in the Q-factor values below one. Originality. New knowledge was obtained about the influence of the rolling route and the full complex of tool calibration parameters in the process of cold pilger rolling of pipes on the distribution of the Q-factor along the length of the deformation cone. Practical value. A method for determining the modes of deformation with an extended compression zone and without a pre-finishing zone is proposed and tested with positive results. This method provides a distribution of the Q-factor along the reduction zone of the deformation cone which is close to uniform distribution and with values above one. The results obtained make it possible to select the conditions for obtaining the required type of metal texture of cold-rolled pipes from titanium alloy Ti-3Al-2.5V using the software product Q-Factor. Cold pilger tube rolling.
Application of laminar structural materials is challenging in the solution of problem of increasing the reliability and life of heavy-loaded machines and equipment. The work deals with the possibility of application of explosion welding for producing myltilayer structures with a high reserve of crack resistance, achieved by control of composition and properties of the joining zone by adding barrier layers. As a barrier layer it was suggested to apply metals, not interacting in solid state or those, forming interstitial solid solutions (vanadium, copper, nickel). The analysis of test results of laminar specimens for low-cycle fatigue under conditions of pulsaring tensile cycle allowed establishing the kinetics of fatigue fracture, depending on structural state of interlayer interface of metal composition. It is shown that adding of an intermediate metal layer, characterized by greatly different properties and increased ductility, to the structure of composition leads to increase in crack resistance of material as compared to the similar equivalent. 5 Ref., 3 Figures.
Mechanical means which are directly related to the information support path (locators, observation stations, accompaniment, detection, localization, etc.) require special attention within the framework of the technical channels of receiving information. Their accurate and stable performance is of the utmost importance. Loss of the mechanical properties occurs during operation, that is material wear. To improve the quality of mechanisms and to ensure the stability of the radio-electronic means, the authors of the paper consider the possible mode of friction geoactivators in the friction unit parts of machines. The studies of the rubbing surfaces chemical composition after being processed by the geoactivator demonstrate that the components of the geoactivator diffuse into the surface layers of the material and form glass-crystalline layers, which are the solutions of the geoactivator components in the phase components of the surfaces steels and cast irons. The studies of mechanical properties have shown that the hardness and wear resistance of the surface layer increases and the roughness of contacting surfaces gets reduced.
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