Open-hearth Furnaces Research Articles

Mathematical modelling of the wear of the tuyere unit in an open-hearth furnace

During the investigation we tried various means of grouping the numbers of tuyeres in the modelling approach; construction of discrete models according to starting information for the operation of the tuyeres, grouped in terms of the substance of the blocks; and construction of a single regression model, using the original information on the operation of all 12 tuyeres. The influence of the subtance of the blocks was studied by building discrete models separately for the left and right sides of the furance; tuyeres 1-6 for which blocks were made from periclase; tuyere 7-12 using periclase-chromite

Periclase blocks for the large zone of open hearth furnaces

Etude de la fabrication de blocs refractaires de periclase: composition des matieres premieres, distribution gramulometrique, caracteristiques des pieces crues, cuisson, composition et proprietes physico-mecaniques des blocs

Deep-blowing of the bath of open-hearth furnaces

Deep-blowing of the bath of open-hearth furnaces

Selected Refractory Advances in Steel-Handling Systems

The iron and steel industry is constantly undergoing technological changes in improving its processes to produce the highest quality world-class steels. As a consequence, the refractories industry has been challenged to keep in lock-step with the iron and steel industry to enhance, not detract from these processes.Certain internal combinations have enabled these refractories changes. Three expositions can display the sophistication to which refractories have advanced, so this article will explore refractories for primary steelmaking, ladles, and slide-gate devices for continuous casting.The start-up of the first top-blown oxygen vessel at the Linz Works in Austria 37 years ago was a historical milestone in the evolution of steelmaking. At that time the open-hearth process was the dominant steelmaking technology in the world. Ten to 12 hours were required to produce one batch of steel in the open-hearth furnace, but only one hour is needed to refine the same amount of steel in a basic oxygen furnace (BOF). In a top-blown BOF all oxygen required for refining is introduced into the vessel through the oxygen lance inserted through the top of the vessel.Toward the end of the 1960s, bottom-blown processes, such as OBM and Q-BOP, became very important in oxygen steelmaking. In the bottom-blown process, oxygen and lime are blown into the steel batch through bottom tuyeres.

Guniting hard-to-reach sections of the lining of open-hearth furnaces

Guniting hard-to-reach sections of the lining of open-hearth furnaces

Change in deoxidation-alloying practice for steel Sv08G2S

Steel Sv08G2S is made in two-trough open-hearth furnaces at the Magnitogorsk Metallurgical Combine. The metal is distributed among the ladles by means of a rocking-type trough which dissipates much of the energy of the stream. This precludes the use of low-solubility ferroalloys or large quantities of same to deoxidize the steel in the ladel. Thus, the deoxidation and alloying (with manganese) of steel in the Sv08G2S is done by a combination method: with carbon-bearing ferromanganese in the furnace and with high-solubility but scarse medium-carbon ferromanganese in the ladle. When the practice of blowing the metal with argon in the ladle was first introduced thus accelerating the dissolution of additions it became possible to attempt to use abundant silicomanganese to alloy the steel. During tapping, the metal was blown with argon at a rate of 60 m~/h through equipment installed in the slide gate. The blowing was continued until the appearance of the furnace slag. The replacement of medium-carbon ferromanganese (22.3 kg/ton) with silicomanganese (24.69 kg/ton) did not significantly change the oxidation losses of the elements of the ferro= alloys. For example, the oxidation losses in the trial and comparison heats were 20 and 23% for silicon and 32 and 31% for manganese.

Methods of reducing manganese consumption during steelmaking in a 600-ton open-hearth furnace

Methods of reducing manganese consumption during steelmaking in a 600-ton open-hearth furnace

Development of a technology for making steel 40Kh in open-hearth furnaces with thorough blowing

Development of a technology for making steel 40Kh in open-hearth furnaces with thorough blowing

System for removing and cleaning flue gases from an open-hearth furnace

The institute VNIPIchermetenergoochistka collaborated with the Magnitogorsk Metallurgical Combine to develop and introduce a gas-cleaning system with an ejector-type Venturi tube. The system transports and efficiently cleans flue gases by the kinetic energy of superheated steam. The low metal content of the system made it possible to make the gas-cleaning equipment and smokestack of stainless steels. The optimum hydraulic operating regime of the Venturi tube was determined for different cross-sectional areas of the de Laval nozzles and different steam consumptions at the nozzles. The low capital expenditures and low metal content make the system feasible for open-hearth furnaces under crowded conditions in existing shops.

Protection from heat radiation in open-hearth shops

Heat radiation studies in open-hearth shops during operations related to servicing the tap hole and cold-charging the furnace were conducted with consideration of the following factors: the capacity of the furnaces; the campaign of the furnace relative to the projected campaign for different furnace capacities; and the variety of manual tasks performed during a shift. Measurements of the thermal radiation were generalized and represented in the form of a nomogram. The results of thermal diagnosis of work stations on the rear platforms of open-hearth furnaces and the cabin of the cold-charging cranes led to the development and introduction of measures to protect workers from heat radiation and improve their working conditions.

Cost efficiency of flame-guniting the lining of open-hearth and electric steelmaking furnaces

The use of flame-guniting for lining repair to the open-hearth and electric steelmaking furnaces of a number of Soviet plants is reviewed. Equipment and technology for flame-guniting the lining of furnaces, which provide for both local and general repairs to the walls, roofs, and bottoms of furnaces, are discussed. Methods are given for calculating expenditures for repair work and determining the cost efficiency of flame guniting relative to the increased number of heats per lining life. Results are given from calculations of the projected cost-efficiency of using flame-guniting for furnace lining repair at the metallurgical plants of the Ukranian Ministry of Ferrous Metallurgy.

Cleaning flue gases from an open-hearth furnace when the bath is blown with oxygen

To develop recommendations on the cleaning of process gases to satisfy health standards, the Magnitogorsk Metallurgical Combine conducted studies of dust and gas emissions from two 400-ton open-hearth furnaces operated by the ore-and-scrap process with subsurface and combination blowing of the bath by oxygen. Oxygen was injected through the combination lateral burners into the flame during cold-charging and heating. Different variants of overhead and subsurface injection lances were evaluated. The results show that the traditional types of gas cleaning (high-pressure Venturi tubes, electrostatic precipitators) can be used with the introduction of the proposed methods of intensifying open-hearth steelmaking with oxygen.

Intensification of open-hearth steelmaking by efficient flame reversal

A flame reversal regime for an open-hearth furnace with heat-transfer half-cycles differentiated according to the period of the heat was introduced at the Il'ich Zhdanov combine 650-ton OH furnaces. The reversals are controlled by a multiposition programmable timer installed in the furnace control panel. A scheme for switching and setting each position of the timer for the corresponding optimum parameter of the different periods was subsequently developed. The flame reversal regime had a significant effect on the productivity of the furnace and fuel and oxygen consumption. The annual saving realized from efficient flame reversal on three 650-ton OH furnaces at the combine has amounted to 141,100 rubles.

Mastering the production of oil-field casing and drill pipe

The Azerbaidzhan Pipe Plant collaborated with the Ukrainian Academy of Sciences and VNIITneft' to develop chromium-silicon-manganese steel 32KhG2SAF hardened by vanadium nitride. The plant also introduced steel processing in 150-ton open-hearth furnaces, teeming of the steel into 4.5-ton ingots, and producing casing and drill pipe from the ingots. The parameters for strength, ductility and crack resistance were examined and it was found that drill pipe made of steel 32KhG2SAF does not require tempering after hot rolling or normalization. The drill pipe was found to have high resistance to cold and fatigue stresses.

Improving the reliability of determination of the soundness of water-cooled elements on an open-hearth furnace

Improving the reliability of determination of the soundness of water-cooled elements on an open-hearth furnace

Production of steel 32KhG2SAF for drill pipe

The Azerbaidzhan Pipe Plant worked with the Ukrainian Academy of Sciences to produce high-strength chromium-vanadium-manganese steel strengthened by nitriding. The steel is made in open-hearth furnaces by the pig-and-scrap process. Cast nitrided ferrochromium is introduced in the metal bath after preliminary deoxidation and is almost completely assimilated. Ferrovanadium is added to the ladle simultaneously with the deoxidizers. The metal subjected to vanadium-nitride strengthening was weldable and was characterized by a good combination of strength and ductility. Dependence of impact toughness, crack nucleation, and crack growth on temperature was also evaluated.

Use of torch guniting for the repair of open-hearth furnace linings

The method and equipment for torch guniting of converters require changes for use in open hearths.

Effectiveness of a new method of fettling the walls and sills of open-hearth furnaces

Effectiveness of a new method of fettling the walls and sills of open-hearth furnaces

Reduction in ingot consumption by warming the ingot top with exothermic materials

the melting period is equivalent to an increase in the consumption of pig iron per heat. This makes it possible to reduce pig consumption without lowering the productivity of open-hearth furnaces or to increase furnace productivity without increasing pig consumption. Under the conditions prevailing in the shop at the Ii'ich Zhdanov combine, the placement of 10-25% of the fresh lime below the main sills and 75-90% above the sills makes it possible to reduce pig-iron consumption by 32 kg/ton, reduce comparison-fuel consumption by 8.7 kg/ton, decrease the consumption of slag-forming, fettling, and refractory materials by 29 kg/ton, and lower the production cost of the steel by 2.61 rubles/ton.

Operation of open-hearth furnaces with regenerators of different designs

lurgical Combine studied the effect of the size of the openings in regenerator checkers on the technicoeconomic indices of 300- and 600-ton open-hearth furnaces fired with natural gas and carburetted fuel oil. The furnaces are operated by the scrap-ore process with 62-64% hot metal in the charge, and they have one pair of regenerators. The volume and heating area of the checkers are 295 m s and 3100 m = for the 300-ton furnaces and 352 m 3 and 3725 m 2 for the 600-ton furnaces. The roofs of the slag pockets and regenerators are made of magnesite-chromite bricks. The walls of the pockets and the top part of the generators are faced on the inside with the s~nne type of brick. The top part of the checkerwork is constructed of T-shaped fireclay brick. The dimensions of the openings in the regenerators are 155 x 155 n~n, 197 x 197 ntm, 230 x 230 ram, and 275 x 275 nnn. The combination method is used to supply oxygen to the flame and to the bath for blowing. To evalute the degree of heat recovery, we measured the temperature of the blower air and the flue gases with suction-type thermocouples. Here, to study the effect of the age TABLE i. Change in the Performance Indices of 300- and 600-ton Open-Hearth Furnaces in Relation to the Size of the Regenerator Checkerwork Openings