METALLURGICAL TECHNOLOGIES
The influence of a low alkaline red mud on the mineralogical composition and physico-mechanical properties of the sinter of banded iron ore JSC “Ural Steel” is determined. Additive of fi ne low alkaline red mud in step batch pelletizing changes the ratio of fi ne and coarse fractions charge upwards large. The growth of strength and reduced abrasion of the sinter is due to the change in the composition of the silicate bond on ferritic bond.
Since using physical modeling analysis the phenomenon of mixing metal and slag in the place argon bubbles output into atmosphere had been explored. It was found that the best results are achieved when the bubble flow purge mode and a diameter of bubbles when they reach the slag phase at 3.25 mm. The mass of the droplets of metal trapped in the slag is 0,6 g, the rate of movement in the slag phase is 1 m/s, while the penetration depth is 3 cm and a residence time is 0,4 sec, which provides optimum conditions for refining of steel in an intermediate ladle. This creates optimum conditions for refining of steel in the tundish. It is shown that under these parameters purge during 1 minute, current line imposed about 50 liters or 350 kg of steel.
During the process of tube drawing takes place adhesive interaction of the metal with the tool. The consequences are defective products and the need for a tool change. The problem of choosing the tool material was examined. The hypothesis of the existence of an analogy between the process of destruction of the friction metal surface in contact friction and well-known process of wetting of a solid metal melt expressed. Based on this hypothesis, an analysis is made of the metal adhesive interaction with the tool. The study shows the contact angle and power characteristics (the work of adhesion, cohesion work) systems carbide (nitride, oxide) – iron metal groups. An estimate adhesive interaction that takes into account the cohesive properties of the metal was described. The criterion for selecting the tool material and the method of tube drawing with sub-micron surface finish was proposed.
Results of the investigation of phase transformations in the slag of sulphuric cupreous melting during its reduction by the products of gasification of carbonic reducing agentsat the temperature 1100 °С are being discussed. It is experimentally found, that in belllike equipment at the temperature 1100 °С he most part of iron from dump slag of sulphuric melting of the cupreous concentrates may be reduced to metallic state by the products of gasification of hydrocarbonaceous carbonic reducing agents. During the indirect reduction of the slag at the temperature above temperature of its melting, metallic iron concentrates mostly at the external surface of product of reduction, producing large inclusions, which may be easy extracted by magnetic separation. It’s mostly rational to reduce multilayer blend, consisting from slag layers less than5 mmthick and separating them layersof grinded coal.
RESOURCE SAVING IN FERROUS METALLURGY
The study describes the problems of energetic efficiency and resource conservation in ferrous metallurgy. Focus is made on energy conservation reserves in blast furnaces and heating and thermal furnaces of metallurgical enterprises.
ECOLOGY AND RATIONAL USE OF NATURAL RESOURCES
The elemental composition of EAF steel dust has been determined by following techniques atomic emission spectrometry with inductively coupled plasma-infrared, absorption method and gravimetric method. Based on these data elemental composition has been converted to oxide composition and oxygen content in the dust has been obtained. In order to identify more complex compounds the reconstruction of composition of the dust has been performed with using program Terra.
INFORMATION TECHNOLOGIES AND AUTOMATIC CONTROL IN FERROUS METALLURGY
ENGINEERING IN FERROUS METALLURGY
On the surface of the slab cross-section 270×1200 mm revealed the presence of bulge narrow faces and tightening wide faces in edge zone at JSC “Ural Steel”. The effect of the length of the supporting system of narrow faces blank on the parameters of distortion of the profi le of the slab was viewed. A statistically significant correlation between the parameters of profi le distortion of the workpiece was established. The deformation mechanism of the workpiece in the limited action of the supporting system below the mold was proposed. Measures to prevent distortion of the profile of the cast slab were considered.
The study shows a laser welding process of slip coating powders of magnesium and aluminum oxides on the surface of the tool steel to enhance and restore its performance. It was found that the thickness of the plastering layer, whereby weld defects are formed coating, depends on processing speed and power of laser radiation. The article includes the recommendations on treatment regimens slip coatings.
MATERIAL SCIENCE AND NANOTECHNOLOGIES
The study describes the diagram of the four-phase composition of metallic system Fe – Si – Mn – B and establishs its mathematical model. Developed computer software allows to calculate the type and quantity of waste of secondary phases in this system with known chemical composition of the metal. Examples of the calculation of the phase composition of boron-containing ferrosilicon manganese, and iron, manganese, silicon, boron impurity elements are shown. The diagram and computer software may be used to form a high deoxidizing ferroalloys and ability doping and selection methods for refining metals from unwanted impurities.
Steels with high boron content are the most used material for the compact storage racks for used nuclear fuel. The influence of the concentration ratio of Ti/B and the cooling rate on the microstructure and hardness of the steel with a high content of boron was investigated. It is shown that the microstructure of steel is composed of particles of (Fe, Cr)2B and TiB2 , uniformly distributed in the ferrite matrix. Increasing the cooling rate leads to a decrease TiB2 sizes from 20 to 2 micrometers and to disperse of the eutectic ferrite + (Fe, Cr)2B and, consequently , increased the hardness.
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