N. D. Karpov

Development of a resistant differentiated lining for steel teeming ladles

ConclusionsA differentiated steel teeming ladle lining with the use in the walls of tar- or pitchbonded heat-treated periclase-chromite refractories has been developed.The life of the ladles with the experimental linings in the shops of Novolipetsk Metallurgical Combine is three and more times greater than the life of the normally used chamotte or rammed quartz-clay ladle linings.The life of lime-periclase linings may be significantly increased the use of measures eliminating skull formation on the refractory lining in service including heating and covering of the ladles with covers during the periods between teemings, the use of special magnesia mortars, etc.

Guniting of the monolithic lining of steel-teeming ladles

ConclusionsThe authors have developed the principles of guniting the monolithic lining of steel-teeming ladles with semidry masses. Determination of the wetting of a vitrified siliceous monolithic lining with aqueous solutions of additives and suspensions of these solutions, plasticizing additives, and refractory filler has shown that a coating can be deposited onto the surface of a monolithic lining. Formation of a ceramic bond between the coating and the vitrified surface of a monolithic lining takes place at high temperatures (900°C or above). Masses of siliceous, aluminosilicate, and periclase-chromite compositions have been developed for guniting the monolithic lining of steel-teeming ladles.A procedure for guniting the monolithic lining of 180- and 350-ton steel-teeming ladles has been developed and tested. The best results have been obtained with use of gunite masses of periclase-chromite composition.

Refractory tubes for protection of metal jets issuing from a steel-pouring ladle during continuous casting

ConclusionsAt the continuous-casting line at NLMW we have tested pouring with a protected stream of metal from the steel-pouring ladle with the aid of quartz and graphite-chamotte tubes. It was established that the optimum design of the protective device consists of a refractory tube 750 mm long in conjunction with a stationary tube fixed on the lid of the intermediate ladle. At the point of junction between the two tubes, inert gas is injected to give additional protection. The structure of the device for bringing the tube up to the ladle should ensure tight joining of the tube with the collector nozzle and mobility of the tube during pouring.

Quartz-clay ramming compounds with quartz sand from the Latnensk deposits

ConclusionsRamming compounds based on Latnensk clay-containing quartz sand and intended for the monolithic lining of steelcasting ladles were developed and tested and are now in production.The average durability of the lining of the 180-ton steelcasting ladles of converter section No. 1 of the Novolipetsk Metallurgical Plant is 9–10 melts when it consists of a ramming compound produced from Latnensk quartz sand. The lining becomes unserviceable owing to the low durability of the working layer of the bottom. When using a ramming compound based on Chasov-Yar semifatty sand, the lining of the lateral parts of the ladle bottom and that of the slag zone are severely eroded after 7–8 melts.

Zircon-graphite nozzles for continuous ingot-casting machines (CICM)

ConclusionsA technology for the production of zircon—graphite nozzles was developed and introduced. This technology is simpler than that used at the Krasnoarmeisk Dinas Plant. Zircon-graphite nozzles are stronger than zircon nozzles and less prone to encrustation during the casting of high-aluminum steel.The characteristics of the zircon-graphite nozzles are as follows: content of ZrO2 57% and C 8–10%, cold-crushing strength 400–600 kgf/cm2, open porosity 18–21%, coefficient of gas permeability 0.075 nPm, refractoriness under a load of 2 kgf/cm2 1640°C, temperature of 4% compression above 1750°C, and thermal-shock resistance six reversals (1300°C — water) before cracking.

The durability of acoustically tested SP-11-type mullite-corundum stoppers

ConclusionsAn investigation carried out at the Novolipetsk Metallurgical Plant of the performance of the SP-11-type mullite-corundum stoppers produced by the Semiluk Refractories Plant showed that the durability was highest in the case of stoppers with a resonance frequency of 10,000–12,000 Hz. The stoppers falling into that frequency range account for about 70% of the total output.Culling out the stoppers with resonance frequencies below 10,000 and above 12,000 Hz and the “deaf” stoppers by acoustic testing increases the performance reliability of the stoppers of pony ladles and lengthens their useful life by 0.25 melt.

The influence of certain factors on the durability of monolithic linings in steelcasting ladles

ConclusionsThe batch composition and technology were developed for monolithic linings for steelcasting ladles.A method of drying the rammed lining of ladles of a capacity up to 180 tons was developed and introduced. In this method the ladle is in the “bottom up” position. The method gives a better lining quality and the drying time is reduced from 16–20 to 10–12 h.The analytical equation is written in the form of the duration and rate of drying as functions of the thickness of the dried part of the lining.An analysis was carried out of the influence of six parameters on the durability of the lining by means of an equation of multiple linear correlation.

Quartzite compositions for the monolithic lining of steel-making ladles

ConclusionsOvruch quartzite and DNPK1 clay are promising materials for ramming compounds. The quality of the compound benefits from the addition of spent sulfite liquor alone or mixed with orthophosphoric acid.The proportion of the fine-ground component in the batch should be 40–50% (including the clay). The proportion of clay should be 10–15%.The slag resistance of the quartzite batch can be increased by adding zircon. The lining of steel-making ladles is more durable when it is produced from quartzite and zircon-quartzite compositions.

Quartz ceramic nozzles for casting steel on continuous casting plant

ConclusionsA technology was developed for making steel casting nozzles for the continuous casting of steel with different versions of lateral input of metal into the crystallizer. In laboratory conditions we made nozzles 600–650 mm long.The testing of the nozzles on continuous steel-casting plant at the Novo-Lipetsk Metallurgical Factory showed that they were highly resistant. It is possible to cast more than 260 tons of steel 3sp and 160 tons of steel 17G2SF through the nozzles, with metal input at an angle of 45° in the crystallizer; through nozzles with horizontal metal input in the crystallizer — 80 tons of steel 17G2SF; and through the nozzle with four apertures — 130 tons of such steel.

Metering component for continuous casting of aluminum-deoxided steel

ConclusionsScale growth in the channel of the metering component during the pouring of steel deoxidized by 2.2–2.5 kg/ton of aluminum is influenced by: the amount and composition of the nonmetal impurities; the material and construction of the component; and the method of supplying the metal to the ingot mold. Stable steel pouring is secured by using a fireclay (36% Al2O3) metering component with widened channel (depth 55 mm), and with full protection against secondary oxidation for the metal stream.