Induction surface hardening of 42CrMo4 steel tubes designed for rotary percussive drilling equipment

42CrMo4 steel tubes are subjected to multiple induction heat treatments to obtain various hardened layer depths after spray water quenching. Current frequency, induction unit power and coil movement velocity along the tube axis are under consideration. The hardened layer depth is estimated along the transverse direction of the tubes using metallographic studies and microhardness measurements. An empirical equation is obtained for the hardened layer depth as a function of the induction heat treatment parameters. The laboratory test results are employed to develop the technology of the production of 42CrMo4 steel tubes designed for rotary percussive drilling equipment. The service life of induction hardened tubes during abrasive wear resistance field tests is approximately twice as long as that of conventionally nitrided ones. © 2016 Author(s)

Study of the two-stage gasification process of pulverized coal at the hydrodynamic flow separation

The paper presents a numerical study of advanced two-stage gasifier with a combined countercurrent and concurrent flow pattern and dry fuel feed system EAGLE. The Kuznetsk coal was used as a fuel for the gasifier under study. We have conducted studies on the influence of the inclination angle of the upper burners in horizontal and vertical planes, and the amount of steam supplied, on heat and mass transfer processes in the chamber as well as on the composition of coal-derived gases. It is shown that the increase in the inclination angle of the upper burners in the horizontal plane allows intensifying the process of two-stage gasification and makes it possible decreasing the height of the chamber without sacrifice of the composition of the coal-derived gases. © Published under licence by IOP Publishing Ltd.Problem statement (section 1 and 2) and results analysis (section 4) were carried out at UrFU and supported by the Russian Science Foundation by Grant 14-19-00524 (M. Chernetskiy and A. Ryzhkov

The dependency of mechanical properties on the microstructure anisotropy index of some alloyed steels

The microstructure banding of the 4340, 42CrMo4 and 20NC11 alloyed steels is estimated using the approach of the ASTM E 1268 standard. The values of the anisotropy index and microhardness are obtained on the longitudinal specimens at various distances from the center of round steel bars with various diameters. Impact strength values in the transversal and longitudinal directions of the bars are obtained. The correlation of the anisotropy index values and the mechanical properties (microhardness and impact strength) of the steels under consideration is derived. © 2017 Author(s).Research are carried out (conducted) with the financial support of the state represented by the Ministry of Education and Science of the Russian Federation. Agreement (contract) no 14.578.21.0114 27.10.2015. Unique project Identifier: RFMEFI57815X0114

Improving the impact toughness of the Hy-Tuf steel by austempering

The microstructure and mechanical properties of the high-strength Hy-Tuf steel are studied after different heat treatment modes - conventional oil quenching and tempering, austempering in the bainite transformation temperature range. It is shown that the tempering embrittlement of the Hy-Tuf steel can be observed at temperatures ranging between 400 and 500 °C. The highest impact toughness of the studied steel for the case of conventional oil quenching and tempering (1.2 MJ/m2) can be achieved after high temperature tempering (600 °C), which also leads to the deterioration of tensile strength down to 800...900 MPa. The unique combination of high tensile strength (above 1300 MPa), elongation (up to 15%) and impact toughness (1.1 MJ/m2) is obtained after austempering at a low transformation temperature. © 2018 Author(s)

The development of a high temperature air heating unit based on the external combustion for integrated gasification combined cycle

The use of heat exchangers in which the working fluid before it enters the gas turbine is warmed up due to the combustion of fuel or other external energy source still is of interest due to the method advantages: the cleanliness of the working fluid; the ability of using cheap low-grade fuels, solar or nuclear energy; the possibility of usage of the closed gas turbine cycle with gases as a working medium, that having favorable thermodynamic properties in comparison with air (helium, CO2, etc.). However, the desired gas turbine inlet temperature - up to 1,700°C currently not possible to provide even with the use of ceramic heat exchangers. Therefore, this technology is now being considered for solid-fuel micro gas turbines operating at temperatures 900-1100°C, or for reducing the need for fuel gas of integrated gasification combined cycle (IGCC) by the means of preheating of cyclic air as well as it is considered for solar gas turbines and gas turbines on the basis of high temperature gas cooled reactors. The authors have developed a metal recuperative air heater based on external combustion of coal for 500 MW IGCC power plant, the development of IGCC is determined by the Energy strategy of Russia for the period up to 2030. In the article the thermal characteristics of the heating of pressurized air, the possible options for the configuration of the heater, heat-resistant materials suitable for its production and the results of the feasibility calculations are considered. In conclusion the design that allows to significantly reduce the specific capital and operating costs for the heater compared to the classic one is proposed. © Published under licence by IOP Publishing Ltd.This work was carried out at the Ural Federal University and financially supported by the Russian Science Foundation (project number 14-19-00524).Comsol;GazEcos;Interenergo;Russian Foundation for Basic Researc

Study of the two-stage gasification process of pulverized coal with a combined countercurrent and concurrent flow system

The paper presents a numerical study of an advanced two-stage gasifier with a combined countercurrent and concurrent flow pattern and dry fuel feed system EAGLE. The Reynolds Stress model was used for the numerical simulation of turbulent flow. We have conducted studies on the influence of upper burner's inclination angle on heat and mass transfer processes in the gasifier as well as on coal conversion. It is shown that the increase in the upper burner's inclination angle in the horizontal plane allows intensifying the process of two-stage gasification. © 2017 The Authors, published by EDP Sciences.Problem statement and results analysis were carried out at the Ural Federal University and financially supported by the Russian Science Foundation (project no. 14-19-00524). The development of methods for mathematical modeling and calculations was carried out with the financial support of the Ministry of Education and Science of the Russian Federation under the Grant Agreement No. 14.607.21.0150 (Unique identifier of the RFMEFI60716X0150

Innovative technologies and principles of criminal proceeding when conducting investigative actions

The discrepancy between the introduction of consumer innovations at the modern level of the criminal procedure minimizes the operation of the principle of criminal proceedings. Purpose of the study is to analyze the use of the problems of introducing innovations in criminal proceedings, as well as the development of norms aimed at improving the mechanism for exercising rights during investigative actions using modern technical means. Methodology: the study of the problem of non-use in the preliminary investigation of modern technologies was carried out using formal-logical research methods, analysis of theory and practice, synthesis and the dialectical method. To develop recommendations for improving legislation, in addition to those listed, comparative and statistical methods were used, as well as interviewing. The main results of the work are: a proposal for the creation of official websites of the preliminary investigation bodies. It was recommended to develop remote investigative actions using video conferencing systems in order to comply with the guarantees of the rights of participants in criminal proceedings; to record investigative actions in modern innovative ways, eradicating the institution of attesting witnesses. The creation of a single base on the blockchain principle will help to avoid a huge flow of information

Experimental and computational study and development of the bituminous coal entrained-flow air-blown gasifier for IGCC

In the paper the development of the advanced bituminous coal entrained-flow air- blown gasifier for the high power integrated gasification combined cycle is considered. The computational fluid dynamics technique is used as the basic development tool. The experiment on the pressurized entrained-flow gasifier was performed by "NPO CKTI" JSC for the thermochemical processes submodel verification. The kinetic constants for Kuznetsk bituminous coal (flame coal), obtained by thermal gravimetric analysis method, are used in the model. The calculation results obtained by the CFD model are in satisfactory agreements with experimental data. On the basis of the verified model the advanced gasifier structure was suggested which permits to increase the hydrogen content in the synthesis gas and consequently to improve the gas turbine efficiency. In order to meet the specified requirements vapor is added on the second stage of MHI type gasifier and heat necessary for air gasification is compensated by supplemental heating of the blasting air. © Published under licence by IOP Publishing Ltd.This work was financially supported by the Russian Science Foundation (project no. 14-19-00524)