Table of Contents



    • Analysis of welding of aluminium alloy AA6082-T6 by TIG, MIG and FSW processes from technological and economic aspect

      pg(s) 194-198

      Welding is a manufacturing process, which uses heat or pressure to form a homogeneous weld when joining homogeneous or heterogeneous metal materials or thermoplastics. The last decade has been characterized by the intensive development of unconventional welding processes, which use friction as an energy source, and in developed countries have taken primacy over conventional welding processes. The modern welding process, known as Friction Stir Welding (FSW), offers many advantages over conventional Tungsten Inert Gas (TIG) and Metal Inert Gas (MIG) processes, both in terms of weld quality and environmental protection and in terms of saving time and materials needed to perform quality welding. This paper presents TIG, MIG and FSW welding technologies, with all the advantages and disadvantages, and the possibilities of their application in welding AA6082-T6 aluminum alloy (6xxx series), characterized by medium strength and outstanding corrosion resistance

    • Determination of the parameters of the drying process of sodium bicarbonate in a pneumatic dryer

      pg(s) 199-200

      This paper describes the process of drying baking soda in a pneumatic dryer. A description of a drying plant with honeycomb elements is provided. Due to the extensive work, only one part of the results of the study is presented, which is related to the material-energy balance, the calculation of the final humidity, the change of the air condition (humidity and temperature) in the bicarbonate drying process. Part of the research results related to the application of I-X – diagram in the drying process of Na HCO3 is presented

    • Innovative design for repair of corrected industrial reinforced concrete structures of light soda silos – Solvay Sodi AD, Devnya

      pg(s) 201-205

      The report discusses the main parameters of a developed design and technological project for the implementation of specific repair and restoration works of built in the mid-1970’s corroded concrete reinforced structures of LIGHT-SODA SILOS – SOLVAY SODI JSC. The purpose of the design is to comply with the requirements for reasonable sufficiency of the additional new steel-reinforced concrete coating (jacked) to realize a lightweight variant of the protective layer against corrosive production factors, atmospheric influences and other specific chemical impacts. The project envisages a technological variant for the implementation of an additional healing thin repair reinforced concrete layer (overlay), based on the specific characteristics of high-tech hybrid fiber-reinforced “wet” sprayed concrete with the participation of specially selected high-range water-reducing and internal-crystallization chemical admixtures. The report provides information on the basic physical-mechanical and technological characteristics of the “wet”-sprayed concrete, as well as the main stages of structural design with specific structural details. According to the static scheme of the facility, it is proposed to specify the allowable loadstate of the structure during the repair works.

    • Regularities of influence of electron beam technology on heat resistance of optical elements in precision instrument-making

      pg(s) 206-209

      Existing experimental researches show that in order to prevent the destruction of optical elements of modern opto-electronic devices (discs as the light filter linings for IR devices, the input protective windows of laser sighting systems for observation in IR areas of the spectrum, semispherical fairings of IR devices for homing and observation of objects, lightguides for laser medical devices, etc.), electron beam method becomes promising, as it provides cleaning of surfaces, increases their microhardness, makes them more resistant to external influences. The results of experimental studies to improve the properties of the surface layers of elements from optical ceramics after their processing with a moving electron beam with a heat density Fn = 106…1.6∙107 W/m2 and moving speed V = 10-3…10-1 m/s (increase in the surface microhardness from 1.2 … 2.9 GPa (raw elements) to 5.7 … 6.4 GPa (processed elements), the occurrence of hardened layers with a thickness of 210… 230 microns). It has been established that the improvement of these properties leads to an increase in the resistance of elements to external thermal effects: an increase of 1.3…1.7 times the critical values of external heat flows and their exposure times, exceeding which leads to the destruction of elements and the failure of devices for the studied range of change of external pressure is 105…107 Pa; increasing the maximum allowable values of thermoelastic stresses in elements from 50…140 MPa to 160…370 MPa at heating temperatures of 300…1200 K.

    • Influence of technological parameters of FDM-print on the strength characteristics of samples of polyamide

      pg(s) 210-212

      The article presents the results of a study of the influence of technological parameters of FDM-printing of samples based on aliphatic polyamide on the deformation and strength characteristics of products based on it. The anomalous nature of the increase in the tensile strength during the destruction of samples obtained by increasing the print speed is shown. A decrease in the strength of the samples was noted with an increase in the number of simultaneously printed products. The main factor determining the strength characteristics of FDM products is interlayer autohesion. The need for the use of materials science solutions that contribute to an increase in interlayer interaction in products obtained by layer-by-layer deposition is indicated.

    • Use of virtual casting for optimization the density of complex geometric aluminum parts, casted in to 3D-printed sand foundry molds

      pg(s) 213-214

      The combined application in a foundry practice of 3D-printing, computer optimization through a virtual casting and modern visualization, by color scales and comparisons allows to be obtained details free of defects from the very first casting. One specific example for a fast optimized casting of a crankcase of aluminum alloy for a turbocharger is shown. The geometry of the detail is of high complexity, developed internal cavities and various wall thicknesses. With the use of three advanced software products, the time to reach the above goal is shortened by about two months and the minimum density in a critical point is increased almost 3 times


    • Steels with bainite structure for railway wheels

      pg(s) 215-218

      Some wheel steels inclined for the self-quenching on bainite structure were produced and investigated after hot deformation and heat strengthening. Steels contained 0,12…0,45% of carbon, and also Si, Mn, Mo, Cr, Ni, V, Ti, Al. Steels with bainite structure after hot deformation and tempering were investigated. It was shown the possibility of the railway wheels production with bainite structure and hardness of 400HB without heat strengthening treatment. The results of investigation shown the possibility of railway wheels production with bainite structure, hardness of 400 HB and high complex of the mechanical and operating properties without heat strengthening treatment. These tasks solved owning to application of new wheel steels and up-to-date technology.

    • Properties of composites with nanodiamonds of detonation synthesis

      pg(s) 219-221

      Modern metals, alloys and polymers, using in mechanical engineering, now have such high-temperature and strength properties that do not meet the advanced requirements. One of the methods to improve their physico-mechanical properties is the method of hardening by dispersed additives. Nanodiamond (ND) and diamond-carbon -containing material (NDC) of detonation synthesis, having nano-structure and high surface energy, impact structurally on any materials contacting with them. Detonation synthesis is a fundamentally new and productive type of basic technology for producing nanostructures and nanomaterials. ND of detonation synthesis is a unique material that combines the properties of diamonds and the advantages of nanostructures. Industrial development of the given method made it possible to actually reach large-volume production and consumption of ND in a number of industries. The effectiveness application of ND and NDC in industrial lubricants, polishing, composite galvano-chemical coatings, metal and polymer-based composites has been shown.