All-Russian Scientific Research Institute of metallurgical heat

A new method has been developed at the VNIIMT for carbon reduction of iron-containing materials in an electric arc. An experimental unit is constructed in order to implement the production process under laboratory conditions. Smelting cast iron from Bakal siderite ore by a non-blast furnace method using original technology is studied.

Thermal strengthening of complex profiles by cooling in water jets is replacing the traditional technology: quenching in oil. This technology has been tested in laboratory conditions and introduced experimentally. It permits the attainment of optimal self-tempering temperature by regulating the cooling time. That permits the creation of metal structures with good mechanical properties and excellent performance.

A physicomathematical model is proposed for the thermal stress of steel rollers quenched after inductive heating. The model involves numerical solution of a system of interrelated nonlinear heat-conduction and thermoviscoelasticity equations. It takes account of the kinetics of austenite decomposition and the specifics of inductive heating. The validity of the model is confirmed by comparing the calculated stress in a roller (diameter 210 mm) with experimental data obtained by the Saks method.

A model of direct iron production by pellet reduction in a shaft furnace has been developed. This model includes the material and energy balances of all the main components of the reduction system (shaft furnace, reformer, etc.) and is based on ARM Tekhnologa software for the analysis and optimization of the reduction conditions at OAO OEMK. The calculation results may be used in the reconstruction of the reduction system and implemented in practice. To predict the reduction conditions and control the direct production of iron, a determinate model of the heat and mass transfer and gas dynamics in the bed is added to ARM Tekhnologa software. This supplementary model simulates the reduction dynamics of a pellet in the shaft furnace and expands the scope for calculating new reduction conditions, so as to boost product output and quality.

The heating section of the hearth in an OK-520 conveyer roasting machine is a complex aerodynamic system, in which the heat carrier passed through the pellet bed consists of the reaction products of natural gas and air (low-temperature heat carrier, 260–300°C) with additional air for dilution (high-temperature heat carrier, 900–1000°C). The volume of the air for dilution and the volume of heat carrier drawn through the bed are unknown. A specified combustion-product distribution over the hearth cross section (above each vacuum chamber) is considered. The interaction of the counterflow antechambers and the burners is analyzed, in terms of thermal stabilization of the heath and the resulting economic efficiency.