RU2088374C1 - Method of making charge billet and casting machine for performing the same - Google Patents

Abstract

FIELD: ferrous metallurgy, namely manufacture of charge billet for steel melting and cast iron production. SUBSTANCE: method comprises steps of continuously feeding solid fillers to cells of molds, pouring them by melt iron through chute; simultaneously charging said solid fillers at least to three cells, feeding filler to central row of cells in quantity consisting 1-1.2 of necessary technological volume and to terminal rows - in quantity consisting 0.9-0.95 of that volume; additionally feeding crushed lime with particle size less than 5 mm in quantity consisting 5-50 kg/t of melt iron to stream of cast iron in zone of draining it out of chute. Casting machine provides feed of equal dozes of solid fillers to mold cells arranged in the same longitudinal row. Said casting machine includes casting apparatus, conveyer supporting molds with cells, hoppers for feeding solid fillers, charging apparatus and drive unit. Charging apparatus is in the form of chain conveyer with pockets arranged under level of chain links of conveyer and at least over three cells of molds for feeding to them dozed solid filler. Drive unit of charging apparatus is in the form of Maltese cross whose axle supports drive pinion of charging apparatus. Said pinion engages with idle gear wheel for transmitting motion to driving sprockets of said apparatus. EFFECT: improved design of apparatus, enhanced efficiency of method. 3 cl, 2 dwg

Description

 The invention relates to ferrous metallurgy and can be used to obtain a billet of billets, which will be used in the future in steelmaking and iron foundries.

 A known method of producing a billet stock for metallurgical processing, including preloading a solid filler, in this case, oxidized iron ore pellets, and subsequent pouring them with cast iron (ed. St. N 985063).

 There is also a method in which the filler through the bottom openings in the feeders enters the cells of the molds of the filling machines and when moving the conveyor, the cells are filled with molten iron (ed. St. N 1105273 prototype).

 However, these methods do not provide uniform distribution of the solid filler in the cells of the molds of casting machines, since the dynamic pressure of a jet of molten iron filling the cells of the molds leads to partial leaching of the filler, its redistribution over the cells of the molds and, as a result, the formation of a billet of different composition in the transverse arrangement cells of molds.

 An object of the invention is to obtain a homogeneous composition in each charge stock, i.e. in all cells both in the transverse and longitudinal sections of the troughs.

 The technical result is achieved by the fact that in the proposed method for producing billets of a given composite composition, the required technological dose of the filler is preselected taking into account the leaching and redistribution taking place under the influence of the jets of molten iron and is loaded into the corresponding cell of the molds, with a volume filler being fed into the central longitudinal row of cells, equal to 1.0-1.2% of the working volume of the cell, and in the extreme rows 0.9-0.95% of the working volume of the cell.

 The filler is selected from the receiver hopper by means of pockets mounted on a double-chain conveyor, the number and location of them in cross section corresponds to the number and location of cells on the molds of filling machines.

 The pockets are made in the form of an unequal pyramid, the open base of which is attached to the links of the chain conveyor, and located below the level of the links. The volume of pockets corresponds to the required dose of filler and, if desired, can be adjusted by setting a false bottom. The pitch of the pockets, the diameter of the driving and driven sprockets, the slope angle of the front wall are chosen in such a way that when passing through a certain area of the driven sprocket, a dose of filler can be poured into the corresponding cell of the mold almost instantly.

 To avoid spills, the extreme walls of the side pockets are provided with scallops, and the front and rear walls of the pockets are made with flanges. Flanges overlap in the direction of the pockets. The level of filling the pockets (100% filling) is regulated by a slide gate mounted on the front wall of the receiver hopper and made of a sufficiently elastic and slightly abradable material. Filling pockets with solid filler is carried out from the hopper-receiver under its own mass of filler. Pockets filled with filler move on a two-chain conveyor in the direction of motion of the molds of the filling machine and, when moving, carry out continuous loading of filler into the mold cells. Synchronization of movement is achieved by means of a device installed on the filling machine.

 Taking into account the existing place of leaching and redistribution of the filler by the action of liquid cast iron, its required dose rate is selected in the corresponding longitudinal rows, for example, filler with a volume equal to 1.0-1.2% of the working volume of the cell is fed into the central row of cells, and 0 in the extreme rows , 9-0.95% of the working volume of the cell. These redistributions are established experimentally.

 Due to the fact that the supply of molten iron is carried out in the central longitudinal row, it, flowing into the extreme longitudinal rows, also captures the filler, and therefore in all rows the ingot is obtained mainly heterogeneous in composition in its entire volume.

 In order to increase the basicity of the slag formed during the redistribution of the charge billet, and refinement of the metal from phosphorus and sulfur, lime fines (less than 5 mm) are additionally introduced into the charge billet. Moreover, the input of lime is carried out in a stream of cast iron when it leaves the gutter nose in an amount of 5-50 kg per 1 ton of molten iron.

 If lime trifle is fed into the gutter on a cast-iron drain, then solid outgrowths of a conceivable conglomerate consisting of lime, slag and solidified cast iron can form on it and on the drain toe. Such growths will interfere with casting.

 If lime trifle is loaded into the molds on pellets (filler), then it will be washed off by cast iron into neighboring molds, thereby violating the uniform distribution of lime in the ingot. Some ingots will contain less lime than set, others more. Practice has shown that the most uniform distribution of lime is achieved by feeding it into a stream of cast iron when draining it from the gutter.

 In the process of melting a billet stock during steelmaking, iron oxides coming from a solid filler and calcium oxides form a slag phase, which simultaneously reacts with sulfur and phosphorus, contributing to the refinement of the melt from the above impurities. The developed contact surface of cast iron oxides accelerates desulfurization and dephosphorization and at the same time allows these processes to be combined. When applying limestone fines with a fraction of less than 5 mm in an amount of less than 5 kg per 1 ton of molten iron, the efficiency of bath refining sharply decreases, because most of the iron oxides is spent on the oxidation of carbon, silicon and manganese cast iron, which leads to a decrease in iron oxides in the slag melt and the deterioration of the dephosphorization process.

 When a lime fraction of less than 5 mm is supplied in an amount of more than 50 kg per 1 ton of molten iron, it is undesirable, since a slag phase is formed in the melt significantly more than the required amount to remove sulfur and phosphorus.

 A known filling machine containing a filling device, molds and a hopper with a feed for feeding the filler, the feeder is a piping system through which bulk materials are fed into the metal stream by gas (Belgian patent N 752378 class. B 22, 1969).

 However, this design does not ensure uniform distribution of the filler.

 A known ingot casting machine comprising a casting device, molds, a hopper with a feeder, the feeder is made in the form of a chute with an opening in the bottom, one end of which is pivotally connected to the hopper, and the other interacts with the mold (ed. St. N 1105273 - prototype). The design of this machine does not allow to obtain a homogeneous heterogeneous ingots system with a uniformly distributed filler over all cells of the molds.

 An object of the invention is the creation of a device that allows to obtain a billet stock of the required composition in all cells of the tundish filling machines.

 The technical result is achieved in that a casting machine for producing a billet includes a filling device, a frame, a conveyor with mounted molds on it, a hopper with a tray for feeding lime stuff on the drain from the gutter to molten cast iron, and a loading device made in the form of a continuously moving a double-chain conveyor with pockets mounted on it, while the chain conveyor of the loading device is driven directly from the conveyor of the filling machine. The drive is made in the form of a Maltese cross. The Maltese cross is in constant engagement with the axles of the axles of the links of the conveyor of the filling machine. The desired direction and speed of the conveyor of the loading device is achieved by a parasitic gear meshed with the gear of the Maltese cross.

In FIG. 1 shows a boot device and a drive, a general view of FIG. 2
section AA.

 The loading device consists of a hopper-receiver 1, which is located in the conveyor area of the filling machine. The Maltese cross 2 is mounted on the frame of the filling machine, is in constant engagement with the axles of the axles 3 of the chain links of the conveyor.

 On the same axis as the Maltese cross 2, gear 4 is planted, which has the ability to transmit rotation through the parasitic gear 5 to the shaft on which the drive sprockets 6 of the loading device are mounted. On the sprockets 6 there is a chain conveyor 7 with filling pockets 8, which is tensioned on the leading sprockets 6 and driven sprockets 9. On the conveyor of the filling machine are mounted molds that have cells 10 (extreme) and 11 (central).

 The boot device operates as follows.

 The solid filler is fed into the receiving hopper 1. When the conveyor of the filling machine is moving, the Maltese cross 2, mounted on the frame and being in constant engagement with the axles of the axles 3 of the chain links of the filling machine conveyor, is driven into rotation and transmits the movement through gear 4 and spurious gear 5 drive sprockets 6 of the loading device, which in turn drive the chain conveyor 7 with filling pockets 8. The pockets passing under the receiving bin are filled with filler and passing through the slaves stars 9, pour filler into the cells 10 of the tundish filling machines. The troughs move on the conveyor, the cells are filled with liquid cast iron and cooled by water mist (shower), knocked out of the troughs and loaded into the iron trucks.

 The proposed group of inventions allows to obtain a homogeneous charge billet in which the solid filler is uniformly located in cast iron in all ingots, cast both in the transverse and longitudinal sections of the molds, to ensure accurate and uniform dosage of the solid filler in the cells of the molds located in different longitudinal rows, as well as receive ingots of a billet of billets that meet the requirements of technical specifications for the composition (solid filler and iron-containing alloy).

Claims (3)

 1. A method of producing a billet stock, comprising continuously loading solid fillers into the cells of a mold conveyor filling machine and then pouring them with a stream of molten iron from the trough, characterized in that the loading of solid fillers is carried out simultaneously in at least three cells, with filler being placed in the central cells served in the amount of 1.2, and in the extreme 0.9 0.95 of the required process volume.  2. The method according to claim 1, characterized in that in the stream of molten iron on its discharge from the gutter, calcareous fines are fed with a fraction of less than 5 mm in an amount of 5 to 50 kg per 1 ton of molten iron.  3. A filling machine comprising a casting device, a casting conveyor with molds with cells fixed on it, a hopper for supplying solid fillers, a loading device placed under the hopper, and a loading device drive, characterized in that the loading device is made in the form of a chain conveyor with fixed on it with pockets located below the level of the chain links of the conveyor over at least three cross-sections of the trough cells for the continuous supply of a dose of solid fillers in the corresponding cell ki and the actuator boot device configured as being in constant mesh with the casting conveyor Maltese cross, the axis of which is mounted the pinion gear meshed with the idler gear that transmits motion to the drive sprocket of the conveyor loading device.

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