Refractory materials for casting diverse steels

Conclusions The investigations demonstrated the advantages of using electrofused periclase and aluminomagnesia spinel for the manufacture of refractory products for casting rimmed steels and of zirconia and aluminomagnesia spinel for refractories for casting killed steels. These findings were confirmed in industrial-scale tests with batching devices and refractory plates produced from these materials.Translated from Ogneupory, No. 8, pp. 22–29, August, 1978.     

Nozzles for equipment for semicontinuous casting of stainless steels under synthetic slag

Summary The most aggressive influence is exerted by synthetic slag on aluminosilicate refractories, and the least — on zirconia and graphite-containing refractories.During the casting of steel under synthetic slag, high-alumina, zircon, and zirconia nozzles were cracked in the first minutes of operation and did not insulate the jet of metal from slag.Alumina-graphite, alumina-silicon carbide and alumina-graphite nozzles during the casting of steel did not crack, were only slightly eroded with slag and metal and provided normal working of the continuous casting plant.Alumina-graphite or alumina-graphite elongated nozzles are recommended for a unit used for the semicontinuous casting of titanium-containing steels involving synthetic slag.     

Service of elongated composite nozzle batchers and nozzles under the batcher insert for continuous steel casting

Conclusions High-alumina composite elongated batcher nozzles containing 62–64% A1₂O₃ satisfy the requirements of casting killed steel. They are being introduced in the continuous steel casting plant of the electric steel casting shop of the Novolipets Metallurgical Factory.The casting of metal in a crystallizer needs to be done through elongated batching devices under a cover, with the maximum degree of sealing and proximity of the metal surface to the tapping hole of the nozzle.Prolonged casting of the unkilled steels type ST2KP and 3KP should be done through elongated high-alumina nozzles containing 80–82% A1₂O₃ with corundum batcher inserts.The following took part in the project: S. A. Krulevetskii, E. I. Ermolaeva, V. V. Parfent'eva, L. N. Baskakova, T. K. Chirkina, N. T. Nikokoshev, Yu. A. Kravchenko, and G. B. Lesokhin.Translated from Ogneupory, No. 2, pp. 21–24, February, 1969.     

Technology for high-alumina mortar in the Belokamensk Refractory Plant

Materials proposed for the production of a high-alumina mortar are investigated, namely, waste of melting of secondary aluminum, polishing powder of normal electrocorundum, and sintered corundum. A technology for the production of high-alumina mortars of three compositions has been developed for these materials. An experimental industrial batch of mortar composed of ShKN chamotte, polishing powder of normal electrocorundum, and DN2 clay has been manufactured and tested with a positive result. Production of the mortar has been introduced in the Belokamensk Refractory Plant.Translated from Ogneupory, No. 1, pp. 27 – 28, January, 1996.     

Refractories for continuous casting of low carbon rimmed steel

Conclusions The compound proportioning device designed by the All-Union Institute of Refractories from an aluminous nozzle containing 80–82% alumina with a porosity of 18–23% and a corundum insert containing 97% alumina with a porosity of not more than 18% satisfies the requirements of continuous casting of low-carbon rimmed steel of the type 05–08KP.Investigations led to the determination of a range of refractories for steel casting and intermediate ladles permitting satisfactory casting in continuous casting plant of low carbon rimmed steel of the type 05–08KP from 140-ton ladles in four shanks with a casting time of about 1.5 h.Translated from Ogneupory, No. 8, pp.4–12, August, 1967.     

Submersible Ladle Nozzles for Continuous Casting Machines: State of the Art and Prospects of Development

The state of the art in the technology, properties, and uses of submersible quartz and corundum-graphite nozzles for continuum steel casting is considered. Corundum-graphite nozzles display a low heat resistance, increased air permeability and, moreover, are environmentally hazardous. The existing methods for updating corundum-graphite nozzles fail to settle the question of channel clogging in casting rimmed steel and other types of steel. Quartz nozzles fabricated by conventional technologies are devoid of these shortcomings; however, they have a shorter life because of the chemical interaction of alloying steel components and their oxides with SiO₂. Comparative tests on submersible quartz nozzles differing in structure and chemical and phase composition showed the emerging potential for new technologies and approaches in the production and uses of updated quartz glass-based nozzles for casting common and low-alloy steels. For casting common steels, updated submersible quartz nozzles are developed with a warranty endurance, under slab CCM operating conditions, of 720 tons (in terms of steel cast) against the rated life of 1200 tons. For low-alloy steels, modified submersible quartz nozzles are recommended with a warranty endurance of 360 tons (in terms of steel cast) against the rated life of 540 tons.     

Developing the production of high-alumina mortar

The St. Petersburg Institute of Refractories has developed a technology for manufacturing a high-alumina mortar of grade MMK85 used for binding high-alumina and corundum refractories. The mortar has been tested under laboratory conditions and shipped to the Volzhsk Pipe Plant for use in equipment of the electrometallurgical complex. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 3, pp. 30–31, March, 1998.     

High-alumina low-fired products based on kyanite — Sillimanite concentrate

Conclusions A technology was developed for making high-alumina low-fired products using kyanite-sillimanite concentrate with a sulfite-lye or orthophosphoric acid bond.The possibility was established of using low-fired brick at service temperatures of up to 1500°C. The tests of these high-alumina products in steel casting ladles of different capacities and in industrial kilns with different service conditions enabled us to establish the most effective locations of their use.Translated from Ogneupory, No. 6, pp. 6–9, June, 1971.     

The wear of magnesia refractories in electric furnaces for melting cast iron

Conclusions The wear of magnesia refractories, i. e., magnesite, perictase — spinel, and magnesite — chromite bricks and magnesite — phosphate mortar, in the walls of electric furnaces for melting cast iron is the result of the solution predominantly of the periclase crystals and to a lesser extent of the spinel in the lowbasicity ferrosilicate slag melt. Brick of the PShS type proved to be the most durable refractory. The use of high-alumina brick in the roof of the furnaces accelerates the wear of the magnesia bricks in the walls.To increase the durability of the lining of these furnaces trials should be carried out with an all-basic wall lining constructed of high-density PShSP-type brick on MF-1-type magnesite — phosphate mortar and a roof lining constructed of MKhS brick and the same mortar.Translated from Ogneupory, No. 4, pp. 44–49, April, 1976.     

Mechanism of wear of corundum and mullite-corundum refractories during stopperless teeming of steel

Conclusions The authors have established differences in the mechanisms of wear of corundum and mullite-corundum plates during stopperless teeming of rimmed and killed steels.They recommend the use of mullite-corundum and corundum plates for stopperless teeming of killed and rimmed steels, respectively.Translated from Ogneupory, No. 3, pp. 22–27, March, 1980.     

The effect of various slaked limes on the microstructure of a lime-cement-sand mortar

The present work aims to provide a better understanding of the effect of both the proportions and the characteristics of slaked lime on the microstructure of a lime-cement-sand mortar. Cement (CPA CEM I 52.5) has been replaced by various categories of slaked lime chosen for the diversity of their physico-chemical characteristics.Cement has been replaced by lime in proportions varying between 0 to 10% of the total binder mass. With very few exceptions, mortars were produced by maintaining the quantity of water constant.Experimental results show that it is necessary to have a high lime substitution percentage to influence the microstructure of the mortar, except in the case of a lime containing magnesium hydroxide or calcic lime featuring sizeable specific surface area.The influence of the nature of the substituted lime on the development of the microstructure in the matrix has been examined by SEM observations of the mortar micro porosity.     

An Air-Setting Refractory Mortar Using a Composite Binder

A composite binder composed of water glass with a hardener and a high-alumina cement is used to prepare an air-setting refractory mortar based on fireclay fillers. The physicomechanical characteristics of the mortar are determined. An analysis of strains induced in the mortar under the first heat-up conditions with allowance made for the change in mortar's mineral structure is given.     

Composite nozzles for casting boiling steel in continuous steel-casting units

Conclusions A technology was devised for the manufacture of composite nozzles for casting boiling steel in continuous steel-casting units. The composite nozzle consists of porous chamotte nozzle (holder) and a high-alumina, magnesite or zircon liner (working part).The composite nozzles with high-alumina liners showed greater durability than other liners during the tests.     

High-alumina mortar from scrap of refractory articles after use in metallurgical units

Scrap of refractory articles of grades MKS-72, MLKh-65, and ShKh-42 after use in steel-teeming and intermediate ladles of the OMK is studied. The possibility of using after-use scrap in the production of mortar is investigated. Experimental batches of high-alumina mortar have been produced and tested with positive results in linings of steel-teeming and intermediate ladles.Translated from Ogneupory, No. 5, pp. 28 – 31, May, 1995.     

Fireclay mortar with a casting binder as a plasticizing additive

A composition of a fireclay mortar with a casting binder as a plasticizing additive is described. Results of a study of the properties of a mortar of grade MSh39 with a composite plasticizing agent (soda ash+LST) and a casting binder are presented. It is established that use of a casting binder in the composition of a fireclay mortar increases the adhesion between the mortar and the refractory, decreases the thickness of the joint, and simplifies the production process of the mortar. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 2, pp. 35–36, February, 1998.     

PHOSPHORUS STEELS FOR VITREOUS ENAMELING*

A summary is given of the tests which were conducted to appraise the utility of phosphorus steels in vitreous enameling. Enameling tests were conducted on both killed and rimmed steels of low-carbon iron and steel with a phosphorus content up to 0.60%. Phosphorus was found to reduce the sag of laboratory-prepared enameling stock to a marked degree. The most effective range of phosphorus was from 0.10 to 0.15%, and killed steels were superior to rimmed steels in their sag resistance. Phosphorus appeared to have no significant influence on common enameling defects. In amounts of less than 0.40%, it had no marked effect on the adherence of the enamel. The deep drawing qualities of the sheet, based on Olsen ductility tests, were somewhat impaired by phosphorus. This is in line with the strong tendency for phosphorus to raise the strength of the sheet.     

Making gate valve refractories for steel ladles using GK alumina

Conclusions A technology was developed for making articles for the gate valves of steel casting ladles ensuring high service factors. It was found possible to use high-alumina chamotte instead of corundum.Translated from Ogneupory, No. 1, pp. 16–18, January, 1980.     

Increasing wear resistance of stoppers for 140-ton steel-casting ladles

Conclusions Among the principal reasons for partial or substantial leaking of the metal stream are the following: burning away of the stopper, breaking off of the spherical part of the head, wear and tear of the head and sleeve bricks and opening up of the seams through deformation of the rod.The stoppers burn away on account of a great deal of wear and tear in the pipes, erosion of the seams, formation of cracks in the pipes and head and deformation of the stopper on account of the rod becoming too hot.The amount of slag in the ladle is one of the main factors for corrosion wear in stopper pipes. The aggressive action in the slag increases as the temperature of the metal and casting time are increased.Breaking off of the spherical part of the head during the first stopper opening due to the formation of skull between the stopper saddle and head can be avoided by using a graphite filling.Insulation of the stopper rod reduces the temperature during casting by 150–300°. The use of good quality mortar in assembling stoppers reduces the erosion of seams, while the use of a high-alumina putty prevents wear in the pipes.     

High-alumina inserts for continuous steel casting

Conclusions High-alumina inserts provide adequate service in the continuous casting of steel and killed carbon steel deoxidized by calcium silicon.In the continuous casting of transformer and killed carbon steel deoxidized by aluminum, the high-alumina inserts did not prove superior to regular chamotte nozzles. Chamotte nozzles with magnesite inserts are unsuitable for continuous steel casting.     

Life of refractories at semi-continuous casting plant

Conclusions High-alumina, zircon, chamotte-kaolin, zirconia, and clay-graphite end nozzles were tested in a semi-continuous casting plant during the pouring of stainless steel in the pouring device, and SP-25 high-alumina and zircon nozzles were tested in the intermediate ladle.For use we recommend the high-alumina nozzles which are considerably cheaper than the zirconia ones.Zircon and high-alumina SP-25 nozzles do not erode when steel is poured from the intermediate ladle, they do not close up and can provide a stream of metal without splatter.