When steel casting by means of sliding gates in an open-hearth furnace was introduced at the OrskoZtmlilovsk Metallurgical Combine, the resistance of the chamotte lining of the 230-250-ton steel-casting buckets was reduced. The reasons for the reduction in the resistance of the lining are the increased time spent by the metal in the bucket and the shorter idling time of the bucket between successive fills; this causes increased wear of the lining under the mechanical and chemical action of the molten metal and slag [1, 2].On the basis of a simulation of the destruction of a refractory lining as a result of temperature and ferrodynamic effects when the liquid metal flows into the bucket, we have now determined the effect of the initial temperature of the lining on the destructive processes. The temperature of the lining was measured using Chromel-Alurnel therrnocouples. The thermocouple junction was embedded in the wall of the bucket to a depth of 35 mm from the internal surface. The thermocouple was mounted at a distance of 1300 mm above the :hearth corresponding to average working conditions of the lining.The temperature was measured during the first fill, the casting, and the cooling of the bucket in air over 2 h 45 rain at 1-5-min intervals. The next series of measurements were made during the third working cycle (filling-casting-cooling) over 3 h 15 min with similar measurement intervals.The temperature of the metalin the initial fill of the bucket was 1600-1615~The statistical data indicated that the average wear on the lining per cast was _< 10-12 ram; the test results showed that the deformation temperature of the brick under a load of 0.2 MPa was 1377~On the basis of the experimental data, we derived the empirical dependence for calculating the temperature of the surface layers of the lining during the heating and cooling process.The cooling of the surface layers of the lining of thickness 15-30 mm after the completion of the steel casting is described by the exponential dependencewhere t is the temperature of the body at the measurement point at a moment of time; to, initial temperaktre of the body; T, cooling time in air; and K, an empirical coefficient (K= 0.0052).However, heating of the lining is a transient process due to gradual damage of the surface layers at the contact with the metal and to the decrease in the liquid metal temperature; approximation of heating of the ladle lining by Eq. (1) therefore leads to high errors. Figure 1 shows graphs of the change in the lining temperature at the site of the thermocouple during the first and third cycles of the ladle operation, and their derivatives with respect to time. Inertia of the heating processes is noted, i.e., the increase in temperature at the measurement point is not observed immediately after the rise of the metal level to 1300 ram, but after a certain delay A~d, which is 5 rain for the first cycle and 3 min for the third, and (other conditions being equal) is determined by the distance from the measurement point to the inner surface of the ...

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The new interest in the use of monolithic linings in steel-casting ladles has been stimulated by the possibility of fully mechanizing the lining operation, replacing expensive refractory-ladle brickwork with natural material or special preparation of masses, and also significantly reducing the labor costs associated with repairing the ladles [1][2][3].The present paper deals with the problem of manufacturing cast linings for 250-ton steeJ ~ casting ladles at the Orsk-Khalilov Metallurgical Combine.* The cast linings were manufactured on a specially designed mechanized assembly consisting of equipment for preparing the self-hardening liquid mixtures and a manipulator for supplying the prepared mixture to the gap between the reinforcing lining of the ladle and the template. The layout of the assembly and the design of the manipulator were developed at our combine.The layout of the mechanized assembly is shown in Fig. I. One feature of the assembly is that during casting the ladle remains immobile, while the even cyclic supply of prepared mixture to the ladle is done by the receiving and dispensing worm of the manipulator mounted on a self-moving car. Before casting, the manipulator is moved over the ladle mounted in the repair pit and is centered; at the completion of casting, it is returned to its initial position, releasing the inlet to the ladle~ This particular arrangement of components has several advantages: The whole assembly occupies only a small area (the construction of the equipment, of course~ is carried out in the actual shop conditions, where space is limited); the supply of the prepared mass using the receiving and dispensing worms provides additional mixing; and the electrical drive of the manipulator worms is significantly smaller and simpler than that of an electrically driven platform under the ladle and it is also more reliable and is accessible for repairs.The equipment for the preparation of the mixture consists of a I0 m s bunker for quartzite, two bunkers of 0.9-m s capacity for the ferrochrome slag and additives, dosing equipment , a mixer, and a system for dosing the liquid components.The design of the mechanized assembly involves an elevated arrangement of the parts where all the raw materials in the mixture are transported from above downwards, passing through all the operations in succession.We used a siliceous filler which binds the material, and a hardener for the manufacture of the cast lining of the steel-casting ladles. As the filler we used Pervouralsk crystalline quartzite, grade ZKM-97 according to Technical Specification 14-8-92--74; as the binder we used water glass to State Standard 13078-81 with a modulus of 2.75-2.80. The hardener for the mass was ferrochrome slag to Technical Specification 14-11-95--74. This new technology for the manufacture of the casting lining included the following operations: the supply and charging of the starting materials, laying down the working layer of the ladle bottom, installing the template, casting the working layer of the lining of the ...

Therefore the direct reason of shutdowns of the unit for dry quenching of coke for cold repairs of the lining is collapse of individual portions of the lining of the prechamber and the slanted passages.The time for relining of the collapsed portions of the lining is significant and the life of the lining repaired in routine repairs does not exceed two years. In connection with this at Novolipetsk Metallurgical Combine to prolong the service life of the most worn portion of the lining, the prechamber, wet guniting of a chamotte mixture with an applied layer thickness of 35-40 mm is used.