Том 46, № 5 (2016)

A model is proposed for calculating the spatial distribution of secondary gaseous emissions around steel plants. The model is based on the maximum-risk principle. The following are the basic factors determining the maximum risk of exceeding the permissible concentration of the secondary emission: the formation of the emissions, the propagation of the emissions; and the falloff in concentration. Fundamental differences in the methods of calculating the propagation of primary and secondary gas emissions are noted. In particular, secondary emissions are generated not by point sources but over the whole region where the concentration of the primary emission exceeds its background value in the atmosphere. The concentration field of secondary sulfuricacid emissions is analyzed for a spatially distributed source on the basis of data from OAO Magnitogorskii Metallurgicheskii Kombinat. The H₂SO₄ concentration is plotted as a function of the distance from the source of the primary emission, for different wind speeds. The functional dependence of the H₂SO₄ concentration on the distance has a clear maximum. The position of the peak and the corresponding H₂SO₄ concentration may be determined for any wind speed if the mean power of the primary emission is known over the specified time interval.

The production of electrolytic manganese dioxide from purified solutions after the leaching of manganese-bearing slurry is investigated. The influence of the anodic current density on the electrolysis of manganese-bearing solutions is determined. The preliminary purification of manganese-bearing solutions before electrolysis is discussed. Purification of the solution at pH 6.5–7.0 ensures the maximum deposition of all the impurities that interfere with electrolysis: copper, zinc, nickel, cobalt, aluminum, phosphorus, arsenic, antimony, iron (III), and iron (II). After impurity deposition, the pulp is filtered; the hydrate deposits are washed; and the filtered liquid is sent for electrolysis to obtain electrolytic manganese dioxide. The samples of electrolytic manganese dioxide are studied by means of X-ray fluorescent analysis, X-ray phase analysis, and scanning electron microscopy. The results show that the electrolytic manganese dioxide obtained in the laboratory with anodic current density I_a = 150–200 A/m² meets all the requirements on a highly active product: the content of the basic component (MnO₂) in the experiments is 95.0–96.5 wt %.

Minimization of the metal consumption in components imposes ever-increasing structural requirements on steel. Accordingly, it is important to study the behavior of structural defects in continuous-cast billet (shrinkage pores, gas bubbles, axial porosity) during deformation. The use of laminar physical models to study the pressure treatment of metals is further developed in the present work. The influence of the strain on defect healing may be assessed by using laminar models together with defect application to the surface of layer n and the analysis of information regarding its distortion. The proposed method is applied to the deformation of continuous- cast bar billet in the first three rectangular grooves of the reduction cell in the 500/370 linear rolling mill at PAO Donetskii Metalloprokatnyi Zavod. On the basis of the experimental data, the existing healing mechanism for axial metal defects may be refined in terms of the total extension and the applied deforming forces.

Essentially, the reduction of iron in the blast furnace and the oxidative smelting of steel in the oxygen converter are opposing processes. In addressing the carburization of iron in the blast furnace and its decarburization in the converter, we consider noninertial control of the zonal blast-furnace processes. A functional relation is established between the parameters of the zonal processes and the parameters of the hot blast, the reducing gas, and the blast-furnace gas. On that basis, the batch and coke consumption and the yield of metal, slag, and gas in unit time may be strictly and continuously regulated. That, in turn, permits monitoring of the ore load on the coke. Noninertial control of the zonal blast-furnace processes by this means permits regulation of the slag’s oxidative potential, the ore load, and the consumption of injected dusty iron oxides and hence reduction of the carbon content in the hot metal to 2.0–2.5% or less. This approach leads ultimately to the creation of a single-stage process from ore to steel.

Stoppers are under test in continuous casting machines at various Russian enterprises so as to determine the influence of the material from which the stopper head is made on the stability of casting and the fluctuations of the metal level in the crystallizer.

A method is proposed for calculating the fatigue life of dies used in hot stamping. Failure is assessed in terms of the strain and kinematic factors. Thermocyclic weakening is taken into account in determining the accumulated plastic strain. A special subprogram permits prediction of the number of cycles to die failure on the basis of finite-element modeling of tool–blank deformation.

Two methods of surface treatment are proposed to improve the technological plasticity of thin cold-rolled carbon-steel sheet: ionic bombardment by low-energy titanium atoms; and epilam coating. Both methods markedly increase the extensibility of the sheet (by a factor of 1.2–1.3), as estimated by the maximum crater depth without cracking in Erichsen tests (from the VG group to values exceeding those for the VOSV group, which corresponds to extremely complex extension, in State Standard GOST 9045–93). This is associated with change in the behavior of the sheet on deformation (with change in the properties of the material) as a result of two processes: the healing of surface defects; and the creation of hybrid nanocrystalline and submicrocrystalline structure in the surface layer. In epilam coating, only the first process occurs; in ionic bombardment, both are observed.