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2020-06-10 Views 355

DETERMINATION OF THE MASS FRACTION OF POTASSIUM AND SODIUM OXIDES IN THE DUST OF ELECTRIC FURNACE FILTERS BY ATOMIC EMISSION SPECTROMETRY WITH INDUCTIVELY COUPLED PLASMA

V. A. MAKAROV, T. K. SAVOSTEENKO     A method of measuring the mass fraction of potassium and sodium oxides in the dust filters of electric arc furnaces by atomic emission spectrometry with the inductively coupled plasma (AES-ICP) was developed. Possibilities of atomic emission spectrometers of iCAP series for determination of potassium and sodium in dust of filters of electric arc furnaces are investigated. A method for converting potassium and sodium oxides into solution is proposed. Calibration of the spectrometer was carried out on aqueous solutions with a known concentration of potassium and sodium. For the preparation of calibration solutions, chemically pure potassium and sodium salts were used. Analytical lines of potassium and sodium free from spectral overlays are selected. A good correlation of calibration graphs is obtained. The developed technique is used to determine the mass fraction of potassium and sodium oxides in the dust filters of electric furnaces. Validation of the methodology was carried out. The repeatability of the results was compared with the repeatability of the standardized methodology. iCAP series spectrometers can be used to determine the mass of potassium and sodium oxides in gas cleaning dust More...

2020-07-18 Views 377

PRODUCTION OF METAL CORD CONSTRUCTION SIZE 7 х 7 х 0,22 ON ROOT MACHINES TYPE RIR –15

O. M. MATVEEV, V. V. SHAPOVALOV, I. V. MUZYCHENKO, O. A. STARKINA      Since the appearance of the reinforcing material for automobile tires and rubber products, such as metal cord, you can observe its constant development. Tougher competition among the tire manufacturers makes it a priority to develop new and unique types of these products with improved technical characteristics. The article describes the development trend in the production of metal cord for large and super – large tires in Belarus since 2007 and up to the present. The purpose of this project is to ensure the delivery of large – diameter metal cord to Belshina OJSC in the required volume. The solution to the problem of fulfilling the volume of deliveries of metal cord with a limited number of equipment while maintaining the quality of products is considered. In the process of work, an alternative scheme for manufacturing metal cord was developed, the selection of technological parameters for tuning and twisting was carried out, and the rope equipment was modernized More...

2020-08-17 Views 400

EXPERIENCE IN CONDUCTING TESTS ON A TORSIOMETER TO DETERMINE THE PITCH OF THE METAL CORD

N. A. Akunets     Hardware production is in continuous improvement: the requirements imposed by consumers stimulate the introduction of new technological solutions and equipment. For metal products produced by hardware shops (metal cord, wire for RVD, side bronzed wire), mechanical properties are important, which determine the strength, ductility and other characteristics of materials. Metal cord has a number of physical and chemical characteristics: the diameter of the metal cord, lay pitch, linear density, deviation from straightness, residual torsion, untwistability, characteristics of the brass coating- chemical composition – coating weight, brass thickness, adhesion, mechanical properties-breaking load, elongation at break. The article describes the procedure for measuring the size of the lay pitch on a torsiometer installed by Metro Com engineering S. p. A., Italy using an upgraded device with ten pulses (resolution of the turn counter = 0.1 rotation of the rotating clamp). Comparative tests of 2x0. 30NT metal cord samples taken from a single coil were performed using a device with a resolution of 0.25 turns and 0.1 turns of the rotating clamp of the installation to determine the pitch of the coil. More...

2020-08-20 Views 398

CLAD ROLLED REINFORCING BARS

E. S. OVCHINNIKOV, I. A. OVCHINNIKOVA       Premature destruction of reinforced concrete structures exposed to aggressive environmental influences is a serious problem, both from a technical and economic point of view. Carbon steel reinforcing bar embedded in concrete is usually not subject to corrosion due to the formation of a protective ion-oxide film that passivates the steel under conditions of strong alkalis in the concrete pores. However, this passivity can be disrupted by chlorides penetrating the concrete, or by carbonation reaching the surface of the reinforcing bar. Then the corrosion begins. An example of a solution to this problem is the replacement of conventional steel reinforcement with clad steel during construction. Through the closely spaced interface of two solid metals, the atoms diffuse with each other at different speeds, at a high temperature, and at a certain pressure. This creates a metallurgical bond between two solid metals, the integrity or «strength» of which depends on the «purity» of the interface between the two metals and on the atoms that make up this «transition zone» or bond. The article investigates plated rebar, to determine the possibility of production in a mill 320 OJSC «BSW – Management Company of the Holding «BMC». To study the new type of reinforcing bars, special types of research were conducted as determining the chemical composition, microstructure, and mechanical properties. The main advantages of this type of product are defined in the article. More...

2020-09-22 Views 381

INVESTIGATION OF THE NATURE OF DEFECTS ON THE OUTER SURFACE OF HEAT-TREATED SEAMLESS PIPES

O. V. ROZHKOVA       Compliance with the quenching technology ensures a high-quality product with the required properties. Violation of the modes of heating for quenching and cooling during quenching leads to the formation of defects such as soft spots and quenching cracks. The presence of soft spots in the metal is unacceptable due to structural stresses and the difference in mechanical properties between the base metal and the defective areas. To remove soft spots, repeated heat treatment is required. Quenching cracks occur due to internal stresses that exceed the resistance to destruction, due to non-simultaneous transformations and thermal expansion and compression. Products with quenching cracks are the final rejects. The article examines soft spots and thermal cracks on the outer surface of seamless pipes formed during heat treatment. The results of metallographic studies of the microstructure in the defect zone are presented, and the genetic and morphological features of defects are determined and studied. The structural heterogeneity was confirmed by Rockwell hardness measurements. Based on the data obtained, the causes of defects were determined. More...

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