Chelyabinsk Metallurgical Combine Research Articles

Study of Microstructure and Mechanical Properties of Boron-Containing Hot-Rolled Steel Reinforcement

Stiffened specifications for quality of reinforcement product are dictated by the contemporary market that is expressed in the introduction of new TU and GOST for manufactured products. When switching to the new GOST 34028–2016 enterprises are forced to abandon the use of traditional steel grades and switch to sparingly alloyed steel with expensive alloying elements (such as vanadium, niobium, molybdenum) with a lower carbon content. However, transition to new steel grades does not always provide the required level of properties and is often associated with an increase in production costs. Results are provided for a study of the structure and properties of A400C-class steel reinforcement made from a test melt in PAO Chelyabinsk Metallurgical Combine. During steel melting it was aimed at minimizing the number of expensive alloying elements and their partial replacement with boron. Results of the study show that microalloying steel with boron and using the standard manufacturing technology for hotrolled steel does not give unfavorable results for finished product properties and structure.

Analysis of Asymmetric Rolling Efficiency for Improving Rolled Strip Accuracy

Technology is analyzed for asymmetric rolling in order to improve rolled strip precision in large units: a 1700 strip cold rolling mill and a Severstal Cherepovets Metallurgical Combine 2000 broad-strip mill; in an ArcelorMittal Temirtau (Kazakhstan) 1700 continuous broad-strip mill. Research demonstrates the efficiency of asymmetric rolling for improving rolled strip precision. In the ArcelorMittal Temirtau 1700 broad-strip mill with asymmetric rolling of strip 2.0–3.0 mm thick non-flatness is reduced on average by 31% compared with symmetrical rolling. Trials of asymmetric strip rolling of corrosion resistant steel 12Kh18N10T in a Chelyabinsk Metallurgical Combine 500/1500×1700 reversing four-roll mill demonstrate the possibility of cold strip rolling with standard flatness with mill adjustment for peripheral speed mismatch of the upper and lower working rolls per pass by 2–7% and simultaneous excess of forward tension over the back tension by 3–7%.

Study of Fluorite-Containing Fluxes by Scanning Electron Microscopy

Scanning electron microscopy is used to study fluxes used in ESSW-6 of the Chelyabinsk Metallurgical Combine for producing refining slag in a steel-pouring ladle during extra-furnace treatment of steel by AKOS (complex steel processing facility). Three forms of flux containing feldspar are studied: fluorite briquettes FB 85 (TU 48-15-29–91) and fluorite concentrates FK 85 and FK 92 (GOST 29220–91). The average specimen chemical composition and its individual fragments are studied. It is established that for extra-furnace treatment of low-carbon stainless steel it is most preferable to use fluorite concentrate F 92 with a high basic element concentration and low (less than 3%) carbon content.

Effect of the Geometry of the Metal Conduits of a Tundish and the Casting Parameters on the Performance of Continuous Section Casters1

This article relates the experiences of the Chelyabinsk Metallurgical Combine and the Pervouralsk New Tube Plant in mastering the operation of continuous section casters. It examines how the startup of the strands is affected by the geometries of the submersible nozzle, the metering nozzle, and adjustments made to the process parameters. Recommendations are given to make the section caster more reliable during startup and casting.

Upgrading of a teeming crane in the BOF shop at the Chelyabinsk metallurgical combine

This article discusses a project being carried out in the BOF shop at the Chelyabinsk Metallurgical Combine to describe the experience of upgrading teeming cranes and increasing their load-carrying capacity. The cost of the upgrades was minimized by maximizing the use of the existing equipment and minimizing expenditures on equipment disassembly and assembly, commissioning, and startup.

Method of calculating and analyzing the factors that affect the coke consumption and productivity of blast furnaces at the Chelyabinsk Metallurgical Combine

Statistical analysis is used to examine the effect of the main raw-material and process factors on coke rate and productivity for the blast furnaces at the Chelyabinsk Metallurgical Combine during the period from 2007 to July 2012. A method is developed for calculating and predicting coke rate and daily pig-iron output in the blast-furnace shop, and a combination of parameters is found to reduce coke rate and increase the productivity of the shop. The factors table which is used throughout the industry is refined for the conditions that exist in the blast-furnace shop at the ChMK.

The Use of Thermal-Imaging Inspection at the Chelyabinsk Metallurgical Combine

Thermal-imaging inspection of electrical equipment and metallurgical production equipment at the Chelyabinsk Metallurgical Combine is examined.

Development of sinter production at the Chelyabinsk Metallurgical Combine

The sinter production facility at the Chelyabinsk Metallurgical Combine has gone through several stages of development, from a waste-recycling plant to a modern complex that makes high-quality sinter. A program for making the sintering operation more efficient has been developed and is currently being implemented. The use of high-quality gas-cleaning equipment has reduced harmful atmospheric emissions per ton of product by a factor of 8–10.

Mastering a Technology for Making Stainless Steel on a VOD Unit at the Chelyabinsk Metallurgical Combine

This article describes the main stages of introduction of a new technology in electric-steelmaking shop No. 6 at the ChMK for making stainless steels in a vacuum-oxygen decarbonization (VOD) unit. It discusses the solutions that were found to different problems, the results that were obtained, and the dynamics of the production of stainless steel by the VOD method.

Technology for restoring the original profile of blast furnaces at the Chelyabinsk Metallurgical Combine

The smelting of charges with a high content of iron-bearing wastes in a blast furnace runs the risk of forming slag crusts in the furnace due to the wastes’ high zinc content. A technology for restoring the original profile of the furnace has been developed and is being successfully used.

Improving the technology for cooling, heat-treating, and conditioning continuous-cast slabs of chromium-bearing ferritic steel

A new technology has been developed, tested, and introduced at the Chelyabinsk Metallurgical Combine to process cast slabs of titanium-free chromium-bearing ferritic stainless steel 12Kh17. The technology includes a decrease in the temperature and duration of the heat treatment administered in furnaces or replacement of that treatment by slow cooling of the steel in stacks near other hot metal. The technology also entails a decrease in the maximum temperature allowed for abrasive conditioning and the elimination of additional and repeat heat treatments. These changes have shortened slab processing time, increased output, expanded the range of rolled products being made, and improved the economic indices of the production process.

Effect of additions on the production cost of steel and the cost-effectiveness of converter steelmaking

This article examines the effect of additional blowing on performance indices and production costs for the production of steel in the converter shop at the Chelyabinsk Metallurgical Combine. It is shown that deviations from prescribed steelmaking practices in the shop, the use of pig iron with an unstable chemical composition and temperature, the lack of information on the pig iron for use by the shop supervisor before the beginning of heats, the cold-charging of scrap with a low bulk density, the use of poor-quality lime, and other problems make it impossible to conduct the blow with the optimum blowing, temperature, and slag regimes. This makes it necessary to take corrective actions: heats are subjected to additional blowings to attain the required temperature and necessary contents of C, S, and P. More than 90% of the heats at the combine require additional blowing “for temperature” and as much as 18% need additional blowing “for phosphorus and sulfur.” It was established that the unit consumption of metallic charge materials and steel production costs are respectively 19.60 kg/ton and 249.39 rubles/ton higher for heats which receive additional blowing.

Effect of microalloying on process ductility of high-temperature alloy KhN62MBKTYu (EP742-ID)

With the aim of excluding defects and scrap during manufacture of disk and plate forgings of steel EP742-ID at the Chelyabinsk Metallurgical Combine work is carried out for studying alloy microstructure (including use of electron diffraction studies) for determining process ductility and the effect of microalloying on alloy process ductility. A connection is established between alloy process ductility and microalloying addition (cerium and lanthanum) content, and their optimum content in starting metal is determined.

Improving the technology used to blend sintering-machine charge materials at the Chelyabinsk Metallurgical Combine

A new blending complex has been designed and built to receive, store, and blend charge materials and deliver them to the batching section of a sinter plant. The equipment of the complex was made by the company Ormeto-YuUMZ (in Orsk). The complex has a rated capacity of 520 tons of charge materials per hour, which during its design and startup corresponded to an increase of 3.0 million tons in the annual output of sinter plant No. 1 after its modernization. Technical modifications were made to increase the amout of raw materials that can be proecessed and improve the quality of the charge materials and the sinter. Among these changes was the replacement of batch-operated machines (gantry cranes and dump-cars) by more efficient continuous machines (a collector, stacker, and blending unit).

Ways of improving oxygen converter lining life to more than 7000 melts in OAO ChMK

Information is provided concerning the reorganization of refractory structures in OAO Chelyabinsk Metallurgical Combine. It is shown that as a result of the measures carried out technical and economic indices of the operation of the main units of the OAO ChMK oxygen converter workshop have improved.

Pumping slag from a hot-metal-car ladle before the pig iron is poured into a converter

Studies were performed at the Chelyabinsk Metallurgical Combine to determine how the operation of making steel in a basic oxygen converter is affected by pumping slag out of hot-metal-car ladles. It is shown that redesign of the transfer troughs of the combine’s blast furnaces and changes made to their linings have significantly improved the separation of metal and slag during tapping, which has in turn reduced the amount of slag that enters the ladles to 100‐120 kg per heat. Two series of heats were conducted with and without removal of the slag. Since the results showed that the pumping operation causes losses of pig iron (≈1.8 kg/ton) while failing to have the desired technological effect, it was concluded that this operation no

Experience of using dry mixes for the working layer of intermediate ladle linings

Results are provided for testing dry torcrete mix grade RANTAL MAG ST for the working layer of intermediate ladle linings under RUP BMZ (Belorussian Metallurgical Plant) and OAO ChMK (Chelyabinsk Metallurgical Combine). Use of dry mixes is markedly simplified due to absence of template heating. The advantages of the proposed method are given in comparison with traditional torcreting.

Mastering a technology for the continuous casting of steel on section casters at the Chelyabinsk Metallurgical Combine

The Chelyabinsk Metallugical Combine has successfully introduced a technology for the continuous casting of converter steel into 100 × 100 and 180 × 180 mm semifinished products. Introduction of the technology required the resolution of several technical problems. Studies were made of the causes of breakouts occurring during the casting of low-carbon steel semifinished products. The reasons that semifinished products made of medium-carbon steels acquire a rhombic shape were also examined.

Use of heating materials in the bottom-pouring of steel

Results are presented from tests of heat-insulating refractories MKRFTIV-600 made by the Sukhoi Log Refractories Plant. The tests were performed at the Chelyabinsk Metallurgical Combine. It was found that the amount of top crop taken is reduced by an amount between 3.0% and 8.0% (abs.), the exact reduction depending on the grade of steel being made.

Improving lining systems for metallurgical equipment

Results are presented from a project undertaken to improve the systems used to line metallurgical furnaces at the Chelyabinsk Metallurgical Combine. The improvements made reduce the unit consumption of refractories and increase the life of the lining in several pieces of equipment: the main furnace used to make corrosion-resistant steels; the argon-oxygen refining unit; the tundishes of the continuous casters in electric steelmaking shop No. 6; the electric furnaces and vacuum chambers in electric steelmaking shop No. 2, and other equipment.