The improvement of operational properties of metal parts during the laser surface treatment can be obtained by modifying the melt with the prepared nano-sized particles of refractory compounds (carbides, nitrides, and others.). It allowsthe number of crystallization centersto be increased, the structure to be grinded and the uniformity of the solidified metal to be raised. It is known that thermocapillary convection promotes the homogeneous distribution of materials penetrating into the molten metal. It is also known that the presence of surface-active substances in the melt influences the character of convection. There is evidence that the structure of flow in the melt depends on the amount of surface-active substances in the metal. Therefore, the studies were conducted to obtain data on the relationship of characteristics of metal processing by laser and the uniformity degree of modifying additives distribution. Using the numerical modeling the effects of characteristics of pulsing laser action on allocation of modifying particles are estimated at the presence of surface-active substance in metal. With the help of mathematical proposed model the following non-stationary processes are considered: heating and melting of the metal, heat transfer in the melt, fluid motion, nucleation and growth of the solid phase after termination of the pulse. During the numerical realization of the model the heat conduction equation was firstly solved. Upon appearance of molten metal the boundary of the liquid phase was determined. Further the coupled equations of convective heat transfer and motion of an incompressible fluid were solved. After the laser pulse termination, the calculations are continued until the complete solidification of the substrate material is achieved. It was supposed that modifying nano-sized particles under the influence of convective flows penetrate into depth of a melt from its surface. The movement and distribution of particles in a fluid was modeled using markers. The movement of the markers was determined by the local velocity of the melt. According to the results of numerical experiments, the effect of the parameters of pulsed laser action on the nature of the flow and distribution of the particles in the melt were determined. Optimum parametersfor the melting of the metalsubstrate by a laser pulse are proposed for various surface-active substances concentrations.

 

The calibrated metal is efficient material for manufacture of details on automatic machines and automatic transfer lines, and also for production of smooth lengthy shafts and axes. Such details are not technological as during the machining and operation they change a form in a type of a curvature. Deformation comes at action of centrifugal forces even from sole weight of details. New constructional materials allow to create rather strong details with the reduced transverse section, but a flexural rigidity of such details significantly decreases. It is very difficult to increase flexural rigidity of actual details. In practice, constructive solutions that are associated with material costs are usually used. In this work the possibility of increase in a flexural rigidity of the cylindrical calibrated bars is considered due to the formation of technological residual stresses. The problem of their use is that residual stresses always exist of two types – stretching and squeezing. If external stresses of stretching increase rigidity of details, then pressure loads reduce it. Therefore, the main task of the work was to find such nature of distribution of residual stresses which would provide increase in a flexural rigidity of the details made of calibrated metal. The geometrical model of a bar consisting of thin-walled tubes of 0.2 mm thick was accepted at model operation of residual stresses. Each tube was loaded with the stretching or squeezing tension which corresponded to value of the experimental definition. At model operation and calculation two schemes of loading were used at which in the surface layers either residual stresses of compression or stretching are formed. Experimental calculation methods established influence of key parameters of calibration on a flexural rigidity of metal. The possibility of increase in a flexural rigidity of the calibrated bars is revealed almost twice when cogging from 5 to 34 %. For 20 % it is possible to increase rigidity at increase in length of the calibrating zone of the tool. The influence of the angle of the working cone of the machine is insignificant (about 10%), and for increasing the rigidity the operating angle of the tool must be reduced.

The paper presents the results of simulation of rolling of balls precise in mass with diameters of 93 and 125 mm in screw calibers in QForm-3D and DEFORM-3D, the stages and initial data of creating a virtual model of ball-rolling mill are described. The stress state of the metal in characteristic points along the rolling axis was analyzed: stress intensity, stress tensor components, average normal stress. The results of mass measurements of balls rolled on new and worn rolls are presented. The quality check of the inner layers of metal was carried out and the hardness of the rolled balls was measured along the vertical and horizontal axes of ball symmetry. Investigation of metal deformation in simulation of ball rolling has shown that heated billet in form of hot-rolled steel rod is well gripped by rolls, rolling process is stable without slipping. Billet metal fills the gauges completely. There are no gaps observed between metal and gauges walls. Breaker cores connecting molded balls are completely separated in the mill rolls. In this case, core is cut by the rolls flange and is pressed into the ball body. Separated ball continues to roll in gauge finishing section, core remains are smoothed, and completely formed ball with a smooth surface appears from the rolls. It was established that in stress-strain state modeling all components of stress tensor have negative value, that is, all components of stress tensor during balls rolling are compressive. Statistical processing of data on weighing rolled balls with a diameter of 93  mm and 125  mm shows that deviation of mass from the nominal does not exceed 1  %. Measurements of hardness along the balls diametric section shows absence of hardness failures in the inner layers of rolled metal, which indicates a good quality of core zone.

 

Technological feasibility of combined process and installation of continuous casting and deformation to obtain high mechanical properties and fine-grained structure of steel sheets for weld pipes are considered. The problem of metal stress-strain state under solidified metal cobbing by the die walls of assembly mold is stated taking into account a force of the liquid phase pulling from the permanent crystallizer of installation. Parameters of cyclic deformation focus for thin slab sheets production, initial data for design and boundary conditions of the problem are given. A design scheme for determining stress-strain state of metal in circular deformation focusis presented. Results are obtained by solving the problem of continuum mechanics by finite element method: flat statement of contact problem of elastic-plasticity was used in conditions of large deformations and displacements.ANSYS software was used to solve the problem. The calculation results are presented in form of stress diagrams along the strip symmetry axis and on part of contact line of deformation focus with the die wall. Regularities of distribution of tangential stresses on contact surface of circular deformation focus are presented. Evaluation of solidified metal flow on the boundary with liquid phase during solidified metal cobbing by die walls is provided taking into account a force of liquid phase pulling from permanent crystallizer. The estimation of stress state scheme of metal in circular deformation focus during thin slab cobbing with a high degree of deformation is described in order to improve quality of steel sheets for weld pipes production. The main parameters of continuous casting and deformation plant for weld pipes steel sheets production are given.

A method of classification of jaw crushers protection devices was developed, based on the following classification criteria: crushing machine subsystem, recoverability of the protection device after operation and necessary setting parameters. Separation of protection devices by subsystems forms an additional level in hierarchical structure of technological process automated control system. At this level, subsystems monitoring operability of crusher with significant deviance of calculated parameters from their nominal value, i.e. in emergency situation are located. Classification of protective devices based on restorability, that is, by ability to restore their properties after restoring of design parameter value, and on parameters of protective devices of various subsystems is necessary to determine the method of protective devices design. Their specific features are also to be taken into account during their implementation. The following parameters were considered: force acting from the crusher jaw side; pressure that occurs in hydraulic system of protective device exposed to the action of a crusher jaw; the moment developed by a crusher drive; current value in the drive of the crusher - for electrical subsystem protective devices; temperature of the crusher motor; frequency range of current consumed by electric motor. The proposed classification improves accuracy of crusher’s condition diagnosis: in terms of direct evaluation, which is the most rapid, based on changes in electrical subsystem parameters; in terms of indirect evaluation, which is more accurate, based on change in crusher output parameters as a whole, with constant parameters of electrical subsystem. Joint use of direct and indirect evaluation of the crusher state increases accuracy and efficiency of crusher control, increasing accordingly reliability of crusher unit as a whole.

Results of the study of metallurgical wastes application as components of welding fluxes are given. Composition and production technology of a new welding flux using silicomanganese slag as a component have been developed. Results of this slag application in manufacture of welding fluxes are presented. In order to study quality of welded seams, metallographic analysis was carried out and the grain size and level of nonmetallic inclusions contamination were determined. Metallographic studies were made with the help of OLYMPUS GX-51 optical microscope in magnification range of 100  –  1000  times. Influence of fractional composition of fluxes on their welding technological properties was studied. Optimal fraction was selected, ensuring low level of contamination of metal of welding seam with non-metallic oxide inclusions, in particular non-deformable silicates and oxides. It has been established that application of welding flux fine fraction in an amount of 30  –  40  % ensures reduction in degree of welding seam metal contamination with non-metallic inclusions. The metallographic analysis of welding seam metal shows that introduction of fine fraction does not affect its structural components. Welding seam metal has a ferrite-pearlite structure; ferrite is presented in form of non-uniform grains elongated in the direction of heat extraction. It was determined that the optimum content of a fraction less than 0.45  mm in the flux is 30  –  40  %. To raise technical and economic indicators, it is suggested to mix fine fraction with liquid glass. Application of ceramic flux made of silicomanganese slag dust of 0.45  mm fraction, bonded by liquid glass, provides reduction in the welding seam metal level of contamination with nonmetallic inclusions. At the same time, increase in its volume from 15 to 40  % does not significantly affect the level of welding seam metal contamination with nonmetallic inclusions and its microstructure. Microstructure of welding seam metal is represented by perlite and ferrite. It was found that fine fraction introduction with use of liquid glass in an amount of 15  –  20  % is optimal in production of ceramic flux.

Relaxation processes in amorphous and nanocrystalline alloys in temperature range of –196  ÷  80  °C have been studied. It was established that in amorphous alloy stress relaxation occurs in two stages. At the same time, decrease in initial mechanical stress in the sample by 5  % only occurs during the holding time of at least 1  hour. An increase in temperature of the sample leads to more intensive relaxation, which is manifested in an increase in rate of mechanical stress decrease. At the temperature of liquid nitrogen, stress relaxation is not observed. It has been established that in nanocrystalline alloy relaxation processes proceed in a similar manner, but relaxation rate is much lower. Dependences of residual mechanical stress on temperature and holding time were studied. It was found that in amorphous and nanocrystalline alloys, areas of stabilization of residual mechanical stresses are observed at small holding time (less than 5 min) in temperature ranges of 50  –  60 and 40  –  50  °C. Increase in holding time leadsto monotonousfall in residual mechanical stresses. Heating up to 40  °C results in complete relaxation of mechanical stresses in the sample 15  minutes after the start of the testing. It is shown that preliminary relaxation of stresses in amorphous alloy leads to decrease in value of mechanical stress relieving during electropulse ipmact in samples subjected to stretching. In nanocrystalline alloy, value of relieving remains practically unchanged under the indicated impact. It is also shown that the observed effect occurs due not only to thermal expansion, but also to change in the value of reversible component of directed structural relaxation. In the course of work it was established that value of mechanical stress relieving in amorphous alloy depends on medium in which electric current impulse is supplied. In particular, in liquid nitrogen medium, decrease in value of relieving is observed. Such a decrease is not observed in nanocrystalline alloy.

In recent years, application of high duration steels, first of all, martensitic and bainitic steels used in manufacturing of parts and structures of crucial function has increased significantly. It is possible to achieve a high duration state by means of effective deformation hardening of steels of various classes at rational use. Understanding of quantitative laws and mechanisms of deformation hardening of steels of different structural classes under active plastic deformation is necessary in terms of targeted formation of structure-phase states and mechanical properties of material. In this work, comparative analysis of structure evolution, phase composition and state of defective substructure of steel with martensitic and bainitic structures under active plastic deformation prior to fracture was performed using transmission electron diffraction microscopy. It was shown that after austenitization at temperature of 950  °C (1.5 hours) and subsequent quenching in oil of 38CrNi3MoV steel and normalization of 30Cr2Ni2MoV steel, a multiphase structure (α phase, γ phase, cementite) is formed, based on martensite of packet morphology (38CrNi3MoV steel) and lower bainite (30Cr2Ni2MoV steel). Obtained quantitative regularities of changes in parameters of steel structure in process of plastic deformation made it possible to carry out studies aimed at analyzing the distribution of carbon atoms in structure of deformed steel. Localization of carbon atoms in martensite structure (38CrNi3MoV hardened steel) and bainite (30Cr2Ni2MoV normalized steel) are revealed. It was established that steels deformation is accompanied by destruction of cementite particles. For hardened martensitic steel, with an increase in degree of deformation, the total number of carbon atoms located in solid solution based on α- and γ-iron decreases, and on structural defects – increases. Redistribution of carbon atoms in steel with bainitic structure with increase in deformation degree consists in growth of number carbon atoms located in α-iron, in defects of the crystal structure, and in intraphase boundaries cementite and its’ subsequent decrease in cementite particles within bainite plates and in γ-iron.

The paper presents the analysis of strain hardening in monocrystals of single-phase disordered alloy Ni₃ Fe. These monocrystals are subjected to compression at room temperature. The compression axis is parallel to [001] crystallographic direction. The strain curve of monocrystals with [001] orientation is characterized by several stages conditioned by a certain sequence of substructural transformations. Ni₃ Fe alloy with monocrystals of atomic short-range order possesses an average value of stacking fault energy. Plastic deformation enables the low-energy evolutionary branch of substructure: plane dislocation clusters → knitted structure → striple structure. The linear stage of the alloy strain hardening is connected with the formation of non-homogeneous knitted dislocation structure. TEM images of this structure allow measuring the free distances between the different dislocation locks formed along the dislocation line due to the dislocation intersections of different slip systems. Using the parameters measured for the monocrystal knitted structure, the contribution of strain-hardening mechanisms to shear stress was evaluated. These mechanisms include dislocation intersection, threshold creep, formation and destruction of dislocation junctions, crossing of Lomer–Cottrell and Hirth dislocation barriers and spot defect generation. The formation laws for long-range stresses and elastic interaction between dislocations were studied and the static and dynamic stress contribution to the total stress was determined. To consider the non-homogeneity of knitted dislocation structure, the contributions are detected individually for its dense and loose areas. The estimation of partial contribution made by each mechanism indicates that the main impact to deformation resistance of monocrystals oriented for multiple slip is made by the dislocation hindering, caused by contact interaction between moving and forest dislocations. The deformation growth enables the density increase in the dislocation locks (thresholds and junctions) along the dislocation line, caused by strain hardening of alloy FCC having an atomic short-range order. 

Increase in productivity and reduction of resource and energy capacity in steel production in converters predetermine development of technological measures and improvement of design of aggregates providing preheating of scrap and other charge materials, intensification of afterburning of waste gases in working space of steelmaking unit and redox processes in liquid bath while maintaining satisfactory durability of blowing devices and lining of the converter. Using fuel-oxygen combustion flames in converter process allows solving a number of multi-purpose technological problems. Combustion of fuel in working space of converter during formation of jet or use of submerged combustion flames significantly changes hydrodynamic pattern in reaction zones and liquid bath. Thermodynamic methods have been used to determine dynamics of combustion processes of gaseous fuels and oxidation of converter bath elements during their interaction with high-temperature flame combustion products. Calculation of the process of flame interaction with chemical elements of the bath was carried out for equilibrium conditions. It was established that use of combustion flames changes composition of gas phase in working space of converter, in which H₂ and H₂O are formed in addition to those traditionally present when oxygen is blown with O₂ , CO, and CO₂ . Presence of these gases changes thermal regime and oxidizing ability of the gas phase. When burning gas-oxygen fuel, optimal composition of initial gas mixture (natural gas + oxygen) should correspond to a ratio of 100  %  CH4   +  69  %  O₂ , while a vapor-gas phase containing 40  % of CO₂ and 60  % of H₂O is formed as a product of oxidation reactions. The total enthalpy of gas-oxygen fuel combustion at converter melting temperatures with oxygen excess ratio of more than 1.0 (up to 2.0) is approximately 200  kJ/mole of the initial reagents, with methane oxidation by carbon dioxide (–7) ÷ (–14.5) KJ/mole of initial reagents) at 1800  K and the process becomes endothermic at temperatures over 2000  K (ΔH₂₂₀₀ = (+7.7) ÷ (15.4) kJ/mole); with water vapor gas oxidation (ΔH_{1800  –  2200} = (+19.5) ÷ (+70) kJ/mole of the initial reagents. Therefore, only when the methane is oxidized with oxygen temperature of flame can be more than 1800 K. Use of carbon dioxide, water vapor as an air oxidizer does not give necessary thermal effect. 

Authors substantiate development of management procedures for the step-by-step processing of iron ore wastes of mining regions that provide a full cycle of rational nature management through the introduction of waste-free and low-waste technologies, followed by reclamation and creation of recreation areas for people. Procedure for operating enterprises has been developed, that consists of structure and sequence of operation stages, sump recovery scheme, technological preparation of equipment, calendar plan. Stages are carried out in parallel and consist of waste recycling, reclamation, search, analysis and selection of tenders for recreational areas development. Waste processing and land reclamation are carried out during operation of mining enterprise. Commissioning of the territories intended for recreation of mining areas population is carried out after enterprise liquidation. Management of step-by-step processing of iron ore wastes for closed enterprises consists of the following stages: search for finance support for technogenic resources utilization and reclamation of disturbed land through the sale of available fixed assets (buildings, structures and equipment) and call for investments, including the state ones. In case of insufficient financing, part of iron ore waste is used as construction or packing material for reclamation. Management of the step-by-step processing of iron ore wastes for the projects under implementation includes non-continuous monitoring of man-made resources formation and land disturbance. When wastes are generated, an analysis of existing technologies aimed at their utilization and reclamation of disturbed lands is carried out. Non-continuous monitoring helps to prevent potential environmental damage. During operation of enterprise, step-by-step development of recreation zones is carried out with its subsequent commissioning after the enterprise liquidation. Based on the proposed management of step-by-step processing of iron ore waste, scenarios for waste-free and low-waste technologies introduction in the Tashtagol District of the Kemerovo Region have been developed. Their simulation was carried out in SciLab. The problem of processing scenarios ranking has been stated and solved.

The features of software of information systems for the work of engineering and technological staff at metallurgical enterprises are considered. The software includes automated workstations, decision support systems, information modeling systems, expertsystems, etc. It is desktop applications written in high-level programming languages (Visual  C#, Visual Basic, etc.). Processing of technological information coming from the enterprise database management server (DBMS) includes the need to solve  Runtime package. However, the functionality, availability, and crossplatform portability requirements for modern enterprise information systems cannot be met in desktop applications that use Windows Forms. This is due to the search for a new technology and means of creating information systems. The most rational is the technology for building web applications based on theASP.NET MVC framework, which allows to transfer mathematical libraries, interaction modules with Microsoft Excel, MATLAB from Windows Forms without modification. The concept of the structure of a web application used in the development of software that meets modern requirements for the operation of information systems is presented. This concept suggests the availability of the following functional areas on the web page: logo and title of the current page, session status menu, functional menu, group operations, notifications and tworkspace.a set of mathematical programming problems, systems of differential equations, problems of mathematical physics, etc. Such tasks cannot be solved with the help of a standard set of mathematical tools for general programming languages. So the development of information modeling systems is carried out by interacting with external software  – Microsoft Excel and MATLAB. The interaction with Microsoft Excel is based on COM Interop technology, which assumes the installation of Microsoft Office software on each client computer. To interact with MATLAB, you must pre-assemble the library in the MATLAB Compiler environment and connect it to the program. The execution on the client computer is achieved by installing the freely distributed MATLAB