Pressing nozzles for high-speed steel teeming

Conclusions The Magnezit Combine has begun production of unfired pressed steel-teeming nozzles, with a channel diameter of 120 mm and height of 400 and 450 mm, made of magnesite paste.These nozzles have been put into service and adopted for high-speed top teeming of steel from a 330 ton ladle in the open-hearth shop of the KMW.Translated from Ogneupory, No. 1, pp. 23–26, January, 1979.     

Guniting the roof of open-hearth furnaces at the Zaporozhstal' plant

Conclusions Laboratory analyses and industrial-scale tests resulted in the development of the technological parameters for guniting the lining of the main roof of 500-ton open-hearth furnaces operated at an accelerated melting cycle.The microstructure of chromite and chrome — magnesite coatings containing low-melting additives was analyzed and the chemical composition and structure of coatings which had served in the roof of an open-hearth furnace were determined.The work carried out at the Zaporozhstal' Steel Plant confirmed the effectiveness and advantages of guniting the roof of large-tonnage open-hearth furnaces.Translated from Ogneupory, No. 5, pp. 28–35, May, 1976.     

Experience in using periclase-chromite refractories in roofs of tilting open-hearth furnaces

The workers of the Azovsta’ integrated iron-and-steel works have determined the causes of early wear of main roofs of open-hearth furnaces. They have resorted to lining the main roofs by periclase-chromite refractories of grade LIIIV produced in Slovakia. The use of refractories of grade LIIIV has increased the endurance of the main roofs of open-hearth furnaces by 100 heats. A petrographic study has shown that the high operating properties of articles made of LIIIV are due to their composition and structure, obtained as a result of the use of high-quality initial materials (chromite ore and magnesite powder) and a modern manufacturing process. Introduction of the developed manufacturing process has increased substantially the endurance of the linings and reduced the number of cold repairs of the open-hearth furnaces and the consumption of refractories. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 6, pp. 34–38, June, 1997.     

钢铁基体镀镍保护材料的研制

镀镍层相对钢铁来说是阴极性镀层，钢铁基体镀镍表面易发生微孔腐蚀。研究了一种水溶性保护材料LP－80N。阐述了其保护作用机理，比较了其与苯并三氮唑、2－巯基苯并噻唑、苯甲酸钠、乌洛托品和重铬酸钾等缓蚀剂的缓蚀效果，研究了水洗、乙醇洗和碱洗对LP－80N缓蚀率的影响，同时研究了LP－80N的使用浓度对缓蚀率和接触电阻的影响。结果表明，LP－80N对钢铁基体镀镍表面具有极好的保护效果，且不影响基体材料的电气性能。     

Magnesia products from powders containing more than 94% MgO

Conclusions Using magnesite powders with large contents of magnesium oxide we obtained high-quality magnesite and periclase-spinel products. Periclase-spinel products obtained from the above powders satisfy the requirements of GOST for the PShSP type of product for the roofs of open-hearth furnaces and electric steel furnaces. Their thermal shock resistance is 7–15 water-heat cycles, compared with 5–7 heat cycles for ordinary periclase-spinel products, which is due to their structural features.Translated from Ogneupory, No. 1, pp. 54–58, January, 1969.     

Dynamic interaction of refractory and molten steel: Effect of alumina-magnesia castables on alloy steel cleanness

High quality alloy steel is an important material needed for social and economic development. It is of great significance to major national projects and defence security. Refractories are used in the smelting process of steel; they are some of the main sources of impurities which have an important effect on the quality of steel. As alumina-magnesia refractories are the main lining materials used for steel refining, the influence of these refractories on the cleanliness of molten steel under dynamic smelting conditions has been studied. The size, quantity, composition, and structure evolution of inclusions in steel are analysed. The results show that after smelting, the content of alloy elements in the steel is stable, and that the total oxygen content and inclusions in the steel are increased by the corrosion of the alumina-magnesia castables. However, the maximum average particle size of the inclusions in the steel was limited to 20?µm, which did not cause large inclusions in the steel or seriously affect the quality of steel. During the dynamic melting process, because of the presence of Si and Mn in the alloy steel, the inclusions changed from homogeneous CaS wrapped Al₂O₃-MgO composite sphere to MnS wrapped egg-shaped structure. The alloy elements in steel were found to be beneficial, as they reduced the effect of alumina and magnesia inclusions on the quality of steel. The results indicate that it is feasible to smelt high quality alloy steel using alumina-magnesia carbon-free castable, and that it would be better to limit the refining time to 45?min during smelting.     

Stabilization of lining elements of the working zone of open-hearth furnaces

Various factors affecting the stability of lining elements of the working zone of the open-hearth furnaces at the Azovstal' Works are studied. The main reasons for damage to the open-hearth furnace tanks are deterioration of the quality (high content of SiO₂ and CaO) of magnesite powders (Satkinskoe deposit) and exclusion of the high-phosphorus cast iron from the conversion process. Damage to the weld bead and charging layer results from formation and modifying transformations of bicalcium silicate. The improvement of the maintenance procedure, production of new bottoms, and charging of the working zone of the open-hearth furnace with magnesite powders imported from Slovakia (the special chemical composition of these powders prevents formation of bicalcium silicate) adopted at the Azovstal' Works make it possible to increase the stability of the lining, substantially decrease the magnesite powder consumption, and reduce the labor input and time for maintenance. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 5, pp. 36–39, May, 1997.     

电吸附除盐法在宁钢厂污水站处理中的应用与研究

电吸附技术是一种新兴的水处理技术,由于其能耗低、操作简单、环保等优点而备受关注。作者采用电吸附技术对宁波钢铁厂废水进行了中试处理实验,实验结果表明：除盐率为87．19％,系统的得水率为81．82％,能耗为1．13kW·h／t,出水指标达到了宁波钢铁厂回用水的要求。验证了电吸附技术除盐效果,从而证明该项技术应用于水质除盐的可行性和技术优势。     

钢渣-石灰石复合硅酸盐水泥的研制

通过研究石灰石掺量对钢渣复合水泥强度和安定性等的影响,确定了钢渣—石灰石复合水泥的合理配比,制备了掺量大、性能优良的钢渣—石灰石复合水泥。结果表明,水泥熟料掺量50%、钢渣35%、石灰石10%的钢渣复合水泥,其各项性能指标均达到32.5R等级复合硅酸盐水泥国家标准要求。     

重构钢渣的胶凝性分析

在炼钢转炉排渣的同时,将一定比例的电炉还原渣和煤渣加入到渣盘中,利用熔融钢渣的余热对钢渣的组成和结构进行在线重构。结果表明,重构处理明显降低了钢渣中的fCaO含量,改善了钢渣的易磨性和压蒸安定性,钢渣粉的28d活性指数提高了10%～20%。     

Production and service testing of magnesite-chrome concrete

Conclusions In addition to magnesite-chrome concretes with periclase cement base, they can also be manufactured using a periclase-spinel cement. These concretes show less initial strength, but they soften to a lesser degree over the range 400 to 1000–1200°, hence after heating their strength is not lower than concrete with a periclase-cement base.The least softening of magnesite-chrome concretes over the given temperature range is shown by those with the addition of magnesium sulphate solution and soluble glass; as the modulus of the soluble glass is reduced, the compressive strength of the concretes under air-dry conditions and during heating increases. To obtain strong concretes, the soluble glass modulus must come within 1,8–2,2.In pneumatic tamping the strength of magnesite-chrome concretes is much greater than in vibration methods.In the spouts of electric steel-smelting and open-hearth furnaces, magnesite-chrome concrete showed a high degree of resistance, and its use for this purpose should be widely recommended.In the walls of an electric steel smelting furnace, the magnesite-chrome concrete was not inferior in strength to magnesite brick. The concrete containing magnesium sulphate was particularly satisfactory in this respect.The positive results of the test show the advisability of using concretes with a magnesium sulphate bond in the walls of electric furnaces with a view to replacing rammed linings made with a tar and pitch bond.The use of concrete for lining arresters in vacuum steel casting ensures satisfactory steel casting and has no effect on the quality of the metal.     

Flexural performance of ring-type steel fiber-reinforced concrete

Steel fiber-reinforced concrete (SFRC) with randomly dispersed, short straight steel fibers hardly fails by fiber yielding, and the postpeak behavior is governed by mechanisms related to fiber pullout. It would be more desirable if more fracture energy could be consumed by fiber yielding at failure. It has been experimentally demonstrated in this research that SFRC with the ring-type steel fibers failed by more energy consuming mechanisms other than fiber pullout. Consequently, significant improvements in flexural toughness were obtained as compared to that of SFRC with conventional straight steel fibers.     

钢渣复合取代矿粉、砂和石用作混凝土掺合料与骨料及其性能分析

用风淬渣粉取代矿粉、电炉渣砂取代混合砂、电炉渣石取代碎石制备混凝土，分析了混凝土的内照射指数、外照射指数、f-CaO含量、沸煮膨胀值、比表面积、密度、含水率、容重、含泥量、泥块含量、坍落度、抗压强度及其化学组成、矿物组成与微观形貌，研究了钢渣的安全性与稳定性及风淬渣粉取代矿粉、电炉渣砂取代混合砂、电炉渣石取代碎石与钢渣复合取代矿粉、砂和石对混凝土性能的影响。结果表明，风淬渣粉、电炉渣砂和电炉渣石的安全性与稳定性满足国标要求，可用于混凝土。当风淬渣粉取代20wt%矿粉、电炉渣砂取代10wt%混合砂和电炉渣石取代20wt%碎石时，混凝土的性能最优。钢渣复合取代矿粉、砂和石的比例合适，可改善混凝土的界面结构密实度，尤其能提高混凝土养护后期的强度。     

不同细度钢渣的活性研究

通过不同的粉磨时间制备出不同细度的钢渣粉,并对其活性进行研究,试验中进行了钢渣活性指数测定、水化热分析、非蒸发水量的测定和氢氧化钙的测定。试验结果表明,在一定的细度范围内,钢渣的细度对其3d的活性几乎无影响,对其28d活性略有影响,但效果不明显。     

Structural characteristics and hydration kinetics of modified steel slag

This study investigates the structural characteristics and hydration kinetics of modified basic oxygen furnace steel slag. The basic oxygen furnace steel slag (BOFS) was mixed with electric arc furnace steel slag (EAFS) in appropriate ratios and heated again at high temperature in the laboratory. The mineralogical and structural characteristics of both BOFS and modified steel slag (MSS) were characterized by X-ray diffraction, optical microscopy, scanning electron microscopy, Raman and Fourier transform infrared spectroscopies. The results show that modification increases alite content in MSS and decreases alite crystal size with the formation of C₆AF₂. One more obvious heat evolution peak appears in MSS's heat-flow rate curves in comparison to BOFS, becoming similar to that of typical Portland cement paste. As a result, its cementitious activity is much improved.     

Influence of steel fibers on the development of alkali-aggregate reaction

This work presents the results of an experimental research concerning the use of fibers in mortar specimens subjected to alkali-aggregate reaction (AAR). Two types of steel fibers (0.16 mm diameter and 6.0 mm length, and 0.20 mm diameter and 13.0 mm length) were used with fiber volume contents of 1% and 2%. Besides the expansion accelerated tests, compressive tests and flexural tests have also been carried out to display the main mechanical characteristics of the fiber-reinforced mortars after being subjected to AAR. Moreover, the microstructure of the specimens was analyzed by scanning electron microscopy and energy dispersive X-ray. The results shown that the addition of steel fibers reduced the expansion due to AAR for the experimental conditions studied in this paper. The most expressive benefit corresponded to the addition of 13.0 mm fibers in the mixture containing 2% fiber content. This fiber volume content also corresponded to the maximum increment in the mechanical properties compared to the reference mortar, mainly for the post-cracking strength and for the toughness in bending. It was observed that the fibers have a beneficial effect on the material, without compromising its main mechanical properties.     

ABSRACTERS

Steel containing sufficient titanium to combine with all of the carbon does not react with vitreous enamels like ordinary low-carbon steel or ingot iron so that white cover-coat enamels, without a ground coat, can be fused on it without blistering or black specking. The titanium content must be more than 4.5 times the carbon content. This steel has been made commercially by the basic open-hearth process, and the requirements for successful manufacture are explained. It is of excellent quality for deep-drawing and does not have a definite yield point even when normalized or annealed so that stretcher strains cannot occur in it. It is not subject to strain aging of any kind, even when strained as much as 17% and aged at 450°F. It is resistant to caustic embrittlement, and to attack by hydrogen at high temperatures and pressures, and it also resists sagging at enameling temperatures better than regular enameling steel or iron. The yield strength of this steel at room temperature as now manufactured commercially is low, but titanium steels of higher strength containing manganese, nickel, and copper are described, which have the same favorable enameling quality. These stronger steels have excellent ductility and toughness, fair weldability, good resistance to strain-aging embrittlement, and better resistance to grain growth at high temperature than the regular titanium enameling steel. Their properties, however, still remain to be checked on commercial heats.     

Preparation and performance of lightweight porous ceramics using metallurgical steel slag

In this paper, porous ceramics with high porosity and low bulk density were prepared by using steel slag and kaolin as main raw materials and polyurethane sponge as template. The effects of steel slag particle size, zirconia addition, the solid content of the slurry, and the addition of polycarboxylic acid water-reducing agent on the properties of ceramics were studied. In addition, by adding a surfactant (Sodium dodecyl sulfate) to form fine pores on the original framework of the three-dimensional network porous ceramic, the shortcomings of the single as well as the uncontrollable density and porosity of the porous ceramic, which are produced by the template method, are improved. When the grinding time of steel slag is 90 min, the content of zirconia is 3% wt, the solid content of ceramic slurry is 64% wt, and 0.6% wt polycarboxylic acid water-reducing agent and 0.4% of surfactant are added, the prepared porous ceramic skeleton is clear and good. The porous ceramic has a low bulk density (as low as 157.869 kg/m³), high porosity (about 94.05%) and high compressive strength (0.2 MPa). The crystalline phase of it is mainly composed of anorthite, gehlenite, forsterite and quartz. The addition of zirconia, water-reducing agent and surfactant only changes the macrostructure of porous ceramics, and does not change its crystal phase composition. The preparation of porous ceramics from steel slag not only solves the recycling problem of steel slag, but also provides a good substitute for main raw materials of porous ceramics.     

Production and use of low-fired stopper tubes

Conclusions Fireclay stopper tubes made by semidry pressing and fired at 800–900° C are suitable for service in steel casting ladles in the open-hearth departments of NTMK. Compared with ordinary low-fired stopper tubes they are more spalling resistant and less thermal conducting.The use of low-fired stopper tubes is economical owing to the reduction in loss and fuel consumption in firing.Translated from Ogneupory, No. 5, pp. 8–10, May 1967.     

以电炉还原渣重构转炉钢渣的胶凝性能

用电炉还原渣在高温重构的转炉钢渣作高活性钢渣胶凝材料,并探讨重构钢渣的水化进程、水化产物和力学性能。试验结果表明：重构钢渣的水化热曲线在水化13-35h都有不同程度的放热峰存在,而未重构钢渣水化72h未见任何放热峰。SEM照片清晰显示相较于未重构铜渣,重构钢渣水化产物数量更多,水化浆体结构更为致密。随着水化龄期的延长,重构钢渣水化XRD图谱中硅酸盐矿物特征峰明显降低,无定形的C—S—H含量提高。重构过程有效改善了钢渣的后期强度,掺重构钢渣水泥的抗压强度的活性指数最高达104．0％。