No abstract

A UDC 669.1 9:620.193AHornblendite rock castings* are being used successfully as a material resistant to abrasive wear. The presence in its structure of a phase with a chain or band member of silicon oxide tetrahedrons provides sufficient chemical resistance for parts in many aggressive media.The chemical resistance of hornblendite castings in a number of aggressive media has been investigated at the S. M. Kirov Ural Polytechnic Institute. Figure 1 shows data on the resistance of a hornblendite casting in boiling solutions of H~SO4, HC1, and HNO 3. As may be seen, in short time tests (up to 5 h) the most corrosive to cast hornblendite is HCI and in long tests HNO 3.Experience has shown that the relative losses of the components of cast hornblendite AI~O 3 and SiO 2 in an H2SO 4 solution are about the same, while in solutions of HC1 and HNO 3 the A1203 dissolves far more actively than SiO 2 . *Hornblendite is a rock which is the waste from beneficiation of iron ore. The main constituent mineral of the rock is hornblende.

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 ...

Monolithic lining of 250-ton steel-teeming ladles was introduced in Orsk-Khalilovka Metallurgical Combine in 1981. The share of steel-teeming ladles with a monolithic lining is 15-20% of the total number of ladles in service.The lining work is done with mechanized equipment by casting of a fluid self-hardening mixture. The composition of the mixture is 97.5-98.5 wt. % ground quartzite and 1.8-2.5 wt. % ferrochrome slag. The density of the waterglass is 1.08-1.15 g/cm 3. The outer dimensions and profile of the pattern provide a thickness of the cast layer in the lower portion of 190 and in the upper of 150 mm. The pouring time is 30-40 min and the length of hold with the pattern 2.5-3.0 h. The reinforcing lining and the working lining of the upper four rows are made of refractory brick [i].

No abstract