Real-time operational control in information management system for flash-
Over the recent five years, the high-strength rails of the new generation of type R65 of steel grade K76F of the production of the plant «MK Azovstal» as well as high-strength rails of type R65 of steel grade 76F of Russian production with their welding in continuous welded track are more and more often laid at the railroads of Ukraine. At the E.O. Paton Electric Welding Institute the comprehensive investigations of weldability of these rails were carried out using flash-butt method with the aim of development of industrial technologies. In welding of all the investigated batches of high-strength rails the required values of mechanical properties of welded joints were obtained at welding modes, characterizing by energy input 1.5-2 times lower than that in welding of rails of previous generations. The welding technology using pulsed flashing was developed providing a highly-concentrated heating and formation of quality joints of high-strength rails of different production, as well as the new generation of machines for flash-butt welding of high-strength rails under the stationary and field conditions was developed. 10 Ref. The laying of high-strength rails of the new generation with their welding in continuous track is more and more widely used at the railroads of Ukraine. Mostly high-strength rails R65 of steel grade K76F of production of «MK Azovstal», as well as high-strength rails R65 of steel grade 76F of Russian production are applied. At the PWI the comprehensive investigations of weldability of these rails were carried out using flash-butt method with the aim of development of industrial technologies for their welding. At the same time, the weldability of modern high-strength rails R350HT produced by well-known companies «Voes-talpine Schienen GmbH» (Austria), and rails VS350Ya 350LDT of «Nippon Steel» (Japan) was also investigated. Table 1 shows chemical composition and mechanical properties of the mentioned steels.In the manufacture of all the investigated rails the advanced technologies of converter production with the continuous casting of steel and continuous rolling are used.For the rails of steel K76F the differentiated hardening and for steel 76F the volumetric one are used. The hardness of layer of steel K76F hardened over the surface of rail head is HV 374-401 (Figure 1
The aim of the work is experimental verification of possibility of using the thyristor frequency converter with direct connection for 37.5 Hz for power supply of two-phase flash-butt welding machine from threephase mains for its uniform loading. For experimental verification and tests the converter was designed according to the circuit with two three-phase full-wave controlled rectifiers connected in an antiparallel mode. The industrial tests were conducted in welding of steel R65 rails using continuous and pulsating flashing during two years at the rail welding enterprise. It was found that the quality of welded joints met the technical specifications. The analysis of plots of changes of effective values of phase currents showed that difference of these values did not exceed ±2 %. At the same time the phase currents were 20 % lower than the current at the load. Thus, the pilot tests of the frequency converter for 37.5 Hz showed its possibility and rationality for application for flash-butt welding, in particular, of railroad rails due to uniform loading of three-phase mains. At that the efficiency of using converter can be significantly increased by applying it in the flash-butt welding machine power transformer, designed for 37.5 Hz. 7 Ref., 3 Figures.
The article deals with the modern approach to creation of system for control of process of flash-butt welding of rails based on statistical analysis of data collection, characterizing this process. In the received data such an analysis allows detecting a number of previously unknown and useful knowledge interpretations (knowledge discovery in databases), required for making decision on the process control. The analysis of causes was carried out which may lead to deviations in the course of technological process and, as a consequence, to violation of the quality of welded butts. To detect these disturbances, two-level control system was proposed. At the lower level in the system of direct digital control the traditional quality control of welded joints is used for «instantaneous» response to the occurrence of rejection and prevention of its further spreading. At the upper level (at the diagnostic center of company «Ukrzaliznytsya») the statistical processing of welding rails protocols is carried out to detect disturbances which are difficult to control by direct measurements. The developed algorithms passed an experimental verification and can be recommended for their further introduction into industry. 5 Ref., 1 Table, 4 Figures. K e y w o r d s : flash-butt welding, two-level control system, control of process parameters, statistical control, technical state of equipment, allowance control Figure 3. coefficients of accuracy K acc of parameters grouped according to machinesFigure 4. coefficients of accuracy K acc of parameters grouped according to RWE
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