Повышение износостойкости резьбового соединения стальных насоснокомпрессорных труб при нанесении минерального покрытия
The work investigates some tribological parameters of the surfaces of friction pairs made of steel, with mineral layers. A comparative study of the friction coefficient of 18CrNiMo7-6 steel specimens with and without a mineral coating is performed. The lowest friction coefficient value was achieved for samples with mineral coating, without HFC hard surfacing before creating a mineral layer, and it was approximately 15% lower in comparison with the samples with HFC hard surfacing, but without mineral coating. The friction coefficient in the temperature range of 30…140 0С, with constant displacement speed of samples with mineral coatings is practically unchanged for every sample type, the variation range does not exceed 0.02, as contrasted with the friction coefficient of the samples with hard surfacing, but without mineral coating. The value of the coefficient of volumetric wear of an aluminum oxide toroid during rotation with disks with some types of mineral coatings was at the level of detection limit (less than 1.2x10-9 mm3/Nm), which is significantly less than the coefficient of volume wear of a toroid during rotation with disks without coating (4-7)х10-8 mm3/Nm.
The article describes the advantages of the new technology of mineral coating of metal products for the friction pair of mechanical systems. It presents the research results of the wear rate of the samples made of 12X13 steel (X12Cr13) with mineral layers, in the experiments with a piston ring sliding inside a cylinder liner with grease. The wear rate of the samples with mineral layers is lower almost by two factors than that of the samples made of grey foundry iron and untreated samples. As the result of slip/rolling abrasion tests of parts with mineral layers under conditions of high contact pressure, a suggestion was made concerning probable mechanics of surface wear.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.