Nowadays there are no standard methods for the determination of abrasion strength and abrasive ability of foundry coke under conditions close to the conditions of coke moving on a conveying belt, conveyer or in a furnace shaft. The present work presents the test method for the determination of foundry coke abrasion strength and abrasive ability. For tests making the coke samples with particle sizes of 40–60 and 60–80 mm were selected from four diff erent coke lots. The testing was carried out in the vibration machine with total amplitude of vibration of 1.6 mm. Vibrator was equipped with a special tool of the form of container with the aluminum plate fi xed at the bottom. It created vibrations which were communicated to the coke sample and created testing conditions. The testing time was 30 min. The fractional losses of coke sample mass indicate its abrasion strength and the fractional losses of aluminum plate – the coke abrasive ability. Obtained values of abrasion strength and abrasive ability after testing were in agreement with M40 strength index. The coke of 60–80 mm size has more abrasive ability than coke of 40–60 mm. At this time, the coke abrasion strength decreases about 22 and 41 % correspondingly for coke of 40–60 and 60–80 mm with increase in foundry coke strength, and the abrasive ability increases by 7.6 and 2.3 times correspondingly.

Abstract. A method and results of measuring the billets profi le are described for the process of slab molding. The phenomenon of separation from the workpiece deforming tool in the area of the deformation zone was recorded at the production of longitudinal welded largediameter pipes. This phenomenon was studied on the separation bending installation. The experiments have shown that the billet in the area of the working gap tool has a complex curvature profi le. The authors have worked out a program for calculating the coordinates and radii of curvature of the surface of the workpiece on photographs of the deformation zone. The curve of the workpiece profi le based on the change of curvature of the punch was determined. The phenomenon of billets separation can be used to calculate the radius of curvature after unloading.

The paper covers specifi c features of up-to-date test methods for metallurgical sinter strength, defi ciencies of these methods, related to issues of overall improvement of sintering and blast-furnace production processes requiring application of sinter fracture models. Theories of liquid melt migration upon sintering as well as features of sinter cake formation are reviewed; a model of metallurgical sinter fracture is suggested as well, which is based on combined use of the model for hard inclusion tension in the matrix along with the fracture model based on Rittinger’s law. Forces applied to sinter lumps in a test drum are determined and a method for adjustment of the sinter fracture model is suggested with use of granulometric properties of products under testing. It is suggested to use probability distribution of fracture model parameters for the purpose of adjustment. Dependences of these parameters from sinter basicity, carbon content in the charge material and limestone lump size are determined.

The main features of the process of screw rolling of steel pipes by a three-roll mill of screw rolling are considered. Taking into account the variety in distribution of specifi c forces at the deformation zone, the calculation method for the deformation parameters of rolling process of pipe liner in the deformation at the mandrel length was deve loped. The design procedure of partial reductions and contact of the metal surface area with the roll in zones of compression in diameter (reduction) and compression of the liner wall, which takes into account the tangential outfl ow of the metal in the gaps between the rollers, are characteristic for rolling processes of thin-walled pipes with diameter ratio of the thickness Dт /Sm wall > 8. The results of the study are intended for industrial use in the production of pipes with the ratio Dt/Sm = 8 – 15 with tolerances on wall thickness ±6 %; diameter ±0,5 %. These results would increase the understanding and especially the process of obtaining thin-walled pipes on pipe-rolling units with roll-off of screw rolling mills.

The authors have investigated the layer-by-layer development of damage of 10G2S1 plate steel during cold plastic deformation by cyclic bending. Deformation cyclic bending was performed according to the scheme of pure bending at symmetric cycle with amplitude of deformation of 5.5 %. The character of changes of the strength properties of steel shows the kinetics of damage in the process of plastic deformation. It was established that in the area of reversible damage the intensity of hardening increases, reaching a maximum value and then decreases. In the area of reversible damage the mechanical properties of steel doesn’t change until destruction. Criterion upper bound of damage is at (0,2 – 0,3)Nр , where Nр is the number of cycles to failure under cyclic tension – compression. The transformation process of the cellular dislocation structure in the passband is selected as a structural criterion of reversible damage.

Macro and micro studies of grate have been carried out at different stages of operation to determine the cause of drastically reduce of service life of the grate kiln trolleys of 40H24N12SL steel due to the changed operating conditions. The study determined the percolation mechanism of corrosion destruction of parts during operation, determined by the course of intergranular corrosion in steel during the operation period of more than 3 months. The authors defi ned surfaces of the part in which the ICC process has the greatest intensity. The estimation of the impact of operating mode of grates on the course of intergranular corrosion is determined. The ways to improve the grates quality are revealed.

The analysis of the service conditions of nuclear power constructions in case of low-cycle fatigue showed, that appearance of macrocrack is inadmissible. The conditions of safe operation require collecting of reliable information about material’s state at the stage of damage accumulation of dispersed microcracks. It was found that a change of the structure, physical and mechanical properties of specimen of steel 08Cr18Ni10Тi leads to changes of elastic waves parameters. The authors suggested diagnostic parameter defi nable by the time of propagation of elastic waves, that makes possible to estimate material state of supervised construction. The proposed criterion can be used for measuring on real objects that are exploited in low-cycle fatigue.

Thermokinetic diagrams of austenite decomposition are necessary to determine regimes of thermal treatment of steel. Building-up of these diagrams by experiments is diffi cult and labour intensive process. In this work the simulation model of process of phase transformations, taking into account the structure of powder steels, and the methodology for computer experiments with diff erent models of steel cooling are off ered. The proposed model allows to determine the kinetic parameters of austenite decomposition for two values of porosity steel according to the isothermal diagrams, and to predict the kinetics of the transformations in this steel as isothermal and continuous cooling. The adequacy of the model was tested on steels with diff erent porosity using published experimental data.

The main objective of the burning process of electrode products is getting burnt products with desired physical and mechanical properties. The authors have determined the mathematical dependences of forming of burnt products quality during their high-temperature heating, and have completed the identifi cation of these dependences on the basis of the experimental data. Adequate models allow us to study the formation processes of the electrode products quality for diff e rent temperature regimes and initial burning conditions, as well as to predict the quality levels of burned electrode products. The comparative analysis of statistical, deterministic and neural networks models to predict the quality of burnt electrode products was made.

The analysis of the causes of the defect “strip ends bending” was made in conditions of hot rolling at the plate mill 5000. The infl uence of kinematic, thermal and geometrical factors on the occurrence of the defect “strip ends bending” was investigated. The infl uence of the misalignment velocity of work rolls to the bending of front end of a rough billet was studied in details. Therefore 1214 tons of rolls (65 slabs) were examined. The infl uence of rolling process parameters and misalignment velocity of the work rolls to the shape of the strip front end for each pass was analyzed. The modes of asymmetric rolling of alloyed pipe steels at the plate mill 5000 have been developed and simulated in DEFORM environment software package. The authors have proposed concrete recommendations. The production tests of developed asymmetric rolling modes were performed with their analysis and correction. This method can be applied to any type of rolling velocity to adjust the upper and lower rollers independently.

The article describes technical and technological advantages of the cooling of coke oven gas using spiral heat exchangers and gas coolers. Based on the analysis of a number of relative and absolute indicators the eff ectiveness of using spiral end gas refrigerators was assessed on the example of «NEXSON GROUP» equipment. The aim was to prove the technical and economic advantages of the cooling of coke oven gas cycle closing using spiral fi nal gas coolers. Achieving this goal is possible with the next sequential addressing number of tasks: to present the procedure of exercising the technological scheme of cooling of coke oven gascycle closing using spiral gas cooler; to compare the main circuit of cooling of coke oven gas cycle closing based on the most representative assessment of performance; and to assess the eff ectiveness of investments aimed at closing of cycle with the cooling of coke oven gas using spiral gas cooler. The article discusses and describes the basic elements of the author’s theory of benefi ts of using the spiral end of the gas cooler for cooling of coke oven gas, supplemented with illustrative material and calculations, providing relevant argumentation base. The authors have made general conclusion about the technical and technological benefi ts and economic feasibility of using the spiral gas coolers for coke production in the case of implementation of such a scheme by the closing cycle of new construction and through rehabilitation of existing facilities. Statements and conclusions of the work can be applied by management of metallurgical holdings for the purpose of theoretical foundation of corporate development programs, as well as regional government to identify ways to increase environmental security in the region and enhance its attractiveness.