The appropriate mathematical model was created for the investigation of lining parameters impact onto metal air-cooling process in chamber furnace. Numerical computing for various lining composition was conducted: fully dense refractory material, made from chamotte brick; refractory ceramic fi bers on the wall and arch with fully dense refractory of hearth; conceptual lining of entire chamber furnace with refractory ceramic fi bers. Processing of the results allowed to illustrate the impact of the lining type on the length of aircooling process, thereby showing possible reserves for accelerating of this process step.

Steel compacted strands and ropes made of them, having high constructive density, high wear resistance, increased tensile and fatigue strength, are widely used in various sectors of the economy: river and sea transport, engineering and construction pre-acceptance, oil and gas, metallurgy, coal industry, etc. The increase of physical and mechanical properties of the strands and the ropes made of them by high degree of fi lling with metal of cross-section makes it possible to use them as a ground wire and high-temperature cables for overhead electric power lines, which can be confi rmed by testing with integrated action on them of factors close to real conditions. Computer modeling can signifi cantly reduce the complexity of the experimental work on the industrial-rated equipment related to the selection of the optimal constructive-geometrical and technological parameters of production, as well as to carry out forecasting service properties of plastically pressed ropes and strands.

The authors have made several experiments of Borodino coal steam gasifi cation in a two-chamber gasifi er with a circulating fl uidized bed damped by the checker. In one of the two chambers the coal was burnt with excess air coeffi cient of 1.25, in another the coal was gasifi ed by steam. Average size of coal pieces was 0.2 mm. The heat acted from the combustion chamber into the gasifi cation chamber through the particulate coolant circulation (fused 0.3 mm) between the chambers. The chambers were fi lled with spherical jets with diameter of 50 mm and porosity of 0.5; electrocorundum particle size was 0.3 mm. Calorifi c value was 8195 kJ/m3. Mechanical underburning was 2 %. Chemical underburning was 5 %. The model of the gasifi er consisting of a system of two equations of thermal balance of the combustion chambers and gasifi cation satisfactorily describes the experiment. The optimum parameters of the gasifi er were found based on the model: the temperature in the gasifi cation chamber – 900 °C, the temperature in the combustion chamber – 1020 °C, the share of coal supplied to the gasifi cation chamber – 0.36, chemical effi ciency – 40 %.

Foundry practice is widely used in iron and steel industry for manufacturing of numerous steel parts that undergo thermal cycling at exploitation. In order to increase their service lives the problem of cracks formation is to be solved. Operation conditions of a steel ingot at cycled impact of high temperatures were analyzed on example of a head part of the gripping device of continuous casting machines. The head part of a gripping device is exposed to intense and not-uniform heating it leading to formation of substantial stresses inside. Due to periodic heating and cooling cycles in the surface layer of the most heated part (the locker) deformation stresses-strains (of elongationcompression type) spring up, resulting in formation of surface cracks after several dozens of cycles. The stressed state of the head part of the gripping device at heating and cooling periods was investigated. It was found that thermal strain in cast metal, resulting from the impact of high temperatures was the reason of cracks formation. It decreases the operational durability of steel cast parts. With due regard to the character and direction of formation of cracks it was suggested to create a layer on the surface of locker’s tooth, by means of strengthening or renewal surface deposition, which can withstand deformation and is devoid of strain concentrators. It seems to be the most promising way of repairing of parts, manufactured by the process of casting.

The study reviews an analysis of factory melting of K52 strength grade pipe steel in Casting and Rolling Complex (the branch of OMK) which demonstrates steel quality infl uence factors. As a basis, the authors have taken data set of 30 melting. Analyzed manufacturing scheme includes setting and tapping in an arc furnace, metal production in a ladle furnace and steel degassing adjusted microalloying, ladle inoculation and also hot-rolling with subsequent sheet-shearing and strip-shearing. It is signifi cant that reject key factors perhaps are fragile and rigid silicate non-metallic inclusions. This study also contains recommendations of reducing silicate non-metallic inclusions content for changes in technological process.

The mathematical method for determining of the optimal technological parameters of cold straightening of steel sheet on the twelverolled sheet-straightening machine is proposed. The calculations allow us to determine the type and the curvature of the neutral line of steel sheet under straightening depending on the rolls’ radius, the pitch between straightening machines’ working rolls, magnitude of the sheet reduction by the upper rollers, the sheet thickness, as well as elastic modulus, yield stress and hardening modulus of the sheet metal. The research results can be used at the metallurgical plants.

As a result of the comparative analysis of “hot crack” defect (“HC”) descriptions in various technological processes, the characteristics were identified that distinguish them from other defects that may be incorrectly identified as “HC” at superfi cial control. It is shown that in welding and metallurgical practice the metallographic research techniques of defect and about defective zones are used for the exact identification and classification of “HC”. In foundry production such research techniques are not used. However, taking into account complexity of formation mechanisms of “HC” and defects like “HC” in mold pieces, detailed study of such methods is required. The common regularities in macro – and a microstructure of surfaces of defect and about defective zone and characteristic features in defects like “HC” in steel shaped mold pieces are revealed. The technique of identification of “HC” in steel mold pieces was developed.

Laboratory studies of influence of the flux-cored wire composition on properties of the deposited layer of steel samples shows that the introduction to the composition of flux-cored 35V9Kh3SF wire of the fluorine-carbon-containing material instead of amorphous graphite leads to a decrease in porosity of the deposited layer and reduces the amount of contained non-metallic inclusions, including stroke oxide inclusions and non-deformable silicates. On the basis of statistical processing of experimental data the dependence of the deposited layer hardness on the carbon equivalent of used flux-cored 35V9Kh3SF wire was determined. As a result of generalization of experimental data the influence of increasing carbon equivalent of flux-cored 35V9Kh3SF wire on the increase in of the deposited layer hardness, the average surface hardness and the microhardness of martensite was established. With increasing carbon equivalent, calculated according to the formula of the Paton Institute of Electric Welding, the deposited layer hardness increases linearly.

Regarding to sintering process the authors have evaluated chemical composition and behavior of the magnesium materials (Bakal-type siderite and Khalilovo-tipe serpentinite-magnesite) during heating to 1200 °С. On the basis of thermograms it was determined that regarding to the siderite much of the heat is spent on the isomorphic carbona te decomposition and to the serpentinitemagnesite heat is spent on the serpentine dehydration. Distinguished feature of the serpentinite-magnesite behavior is formation of forsterite accompanied by heat in the temperature range of 800 – 850 °С. The authors have considered and argued the possibility of using the compound magnesium mixture at the sintering production.

The article describes the studies the evaporation of components in molten iron and Fe – Cr, Fe – Ni, Fe – Cr – Ni systems in plasma spot area during processing of low-temperature argon plasma treatment. A series of experiments was carried out with different weights of the treated metal. changing the arc power of the plasma torch determine the conditions under which stability of treated metal surface is achieved. The results showed that for the experimental conditions under which the plasma flow completely washes the surface of the metal droplets are most suitable: arc power is not less than 2.0 kW and metal sample mass is in the range of 5 to 10 grams. The dependence between evaporation process and chemical composition of melts was studied. Also, evaporation rate constants were determined. It was found that the greatest rate of evaporation in a neutral atmosphere of a laboratory plasma furnace have Fe – Cr – Ni. It was determined the temperature of the melt surface by the indirect method – the evaporation rate. The surface temperature of the melt which was treated by plasma torch varied in the range from 1950 to 2100 K for changing the arc power in the range of 1.6 to 2.4 kW.

The work considers the possibility of production of bimetallic composite material (BCM) with a base of low carbon micro-alloyed steel and cladding layer of alloy nitrogen corrosion-resistant two-phase austenitic-ferritic steel. The authors have tested the technology for producing bimetallic material by deposition under a layer of flux and subsequent hot rolling. The microstructure, mechanical and corrosion properties of the bimetallic composite material were investigated. It is shown that the proposed material is inferior in corrosion resistance to existing bimetallic materials, and its superior on the strength properties to conventional composite materials is 20–30 %.

Thermodynamic analysis of oxygen solutions in nickel alloys containing cobalt and chromium was carried out. The equilibrium constants of interaction of chromium and oxygen, their activity coefficients at infinite dilution and the interaction parameters for melts of different composition at 1873 K were determined. The dependences of oxygen solubility on the contents of cobalt and chromium in the studied melts were calculated. The deoxidation ability of chromium slightly decreases with increasing cobalt content in melt. The oxygen solubility curves in the Ni – Co melts contai ning chromium pass through a minimum whose position shifts to the higher chromium concentrations with an increase in the cobalt content in the melt.

It is shown for the amorphous alloy Fe78Ni1Si8B13 that the level of initial bending stresses has a significant influence on the relaxation process during annealing: the higher stresses cause the higher degree of their relaxation and the lower critical temperature of relaxation Тσ .

The influence of alloying elements on the content of dissolved nitrogen in the reinforcing steel and the degree of strain aging were investigated. The high efficiency of boron addition in reinforcement steel was determined.