RU2426620C2 - Continuous metal strip production plant - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metallurgy. Proposed plant comprises intermediate ladle (1), intermediate device (2) to feed melt via nozzles (4), teeming rolls (5), thermocouple to measure coolant temperature and coolant flow rate metre, device to heat teeming roll surface (16), pyrometer (17) to measure roll surface temperature, device to control metal level (28), mechanism to adjust clearance between teeming rolls, and teeming roll automatic control system. Teeming rolls (5) are provided with lateral vertical walls (14) are made up of high-temperature thermal tubes with coolant fed onto rolls. Nozzles (4) of intermediate device (2) represent refractory nozzles with slots.

EFFECT: reduced volume of rejections.

2 cl, 3 dwg

Description

The invention relates to metallurgy, in particular to installations for producing continuous metal tapes.

A known installation for producing metal tapes [1. Filonov M.R., Anikin Yu.A., Levin Yu.B. Theoretical Foundations of the Production of Amorphous and Nanocrystalline Alloys by Quick Quenching M .: MISIS, 2006.28 p. See page 6], containing a filling device with a rectangular nozzle, a drum-cooler with a drive.

A disadvantage of the known installation [1] is the formation of a tape crust on the surface of one drum-refrigerator and the inability for this reason to deform the tape. In addition, the presence of one drum-refrigerator limits the heat sink from the metal of the tape.

Known installation CASTRIP for casting low carbon steels [2. Sosinski D. J., Kembell P., Mahapatra R. et al. CASTRIP process - recent advances in the industrial installation of the Nucor steel plant // Metallrug. 2008. No. 12. S.43-46], comprising a bucket, an intermediate bucket, an intermediate device with nozzles, casting rolls, a hot chamber, pulling rolls, a hot rolling mill, a secondary cooling zone, scissors, heating rollers, coilers.

A disadvantage of the known installation is that it does not provide a uniform structure in thickness and width of the tape, it does not provide a uniform thickness of the sheet, which leads to marriage of the sheet of tape: cracks, the possibility of warpage.

The causes of marriage of a sheet of tape are:

- insufficient cooling efficiency of the casting rolls, leading to an unacceptably high surface temperature at a selected metal casting speed;

- uneven cooling of the surface of the rolls along their length, which creates a temperature difference of 10-15 ° C;

- uneven pouring of metal into the space between the rolls along their length;

- unacceptably high fluctuations in the level of metal in the rolls - by 5-10 mm;

- unacceptably high overheating of the cast metal - at 100-150 ° C.

The objective of the invention is the elimination of defects in cracks and warping due to the achievement in the installation for continuous metal strip technical results: effective cooling of the casting rolls, to ensure the required surface temperature at a selected metal casting speed, uniform cooling of the surface of the rolls along their length.

The problem is solved due to the fact that in the installation for producing a continuous metal strip containing an intermediate ladle, an intermediate device for supplying melt with nozzles made in the form of nozzles of refractory material with slotted holes, casting rolls with a mechanism for adjusting the gap between them, a hot rolling mill , secondary cooling zone, guide rollers, coilers, device for heating the surface of casting rolls, pyrometer for measuring the surface temperature of rolls, regulators a cooler for cooling medium flow, a thermometer for measuring the temperature of the cooling medium, a pair of side walls, the following differences are provided: casting rolls are made in the form of high-temperature heat pipes with a coolant supply, a device for controlling the level poured into the casting rolls of metal is connected to an automatic control system casting rolls.

In addition, the surface of the rolls is coated with heat-resistant steel with a thickness of "δ", such that δ / R = 1 / 25-1 / 20, where R is the radius of the casting roll.

There is a causal relationship between the set of essential features of the claimed object and the achieved technical result, namely, due to the fact that the casting rolls are made in the form of high-temperature heat pipes with a coolant supply, efficient cooling of the casting rolls is ensured, which ensures the required surface temperature at the selected casting speed metal. It also provides uniform cooling of the surface of the rolls along their length. A device for controlling the level poured into the casting rolls of metal, connected to the automatic control system of the casting rolls, eliminates fluctuations in the level of metal in the rolls.

Application of a heat-resistant material, such as Cr30Ni70, to the surface of the rolls increases the service life of the rolls and increases the overall efficiency of the process for producing a metal strip. The decrease in the ratio δ / R <1/25 (where δ is the thickness of the coating of heat-resistant material, R is the radius of the roll), makes it difficult to mount the coating on the surface of the rolls and leads to irrational reduction of its service life before repair of the rolls,

An increase in the ratio δ / R> 1/20 leads to an irrational increase in the thickness of the coating, which impairs the thermal work of the rolls as high-temperature heat pipes.

The technical essence and principle of operation of the proposed device are illustrated by drawings, in which figure 1 shows the appearance of the inventive installation; figure 2 is a view aa in figure 1; figure 3 is a longitudinal section of a casting roll.

The inventive installation consists of an intermediate ladle 1, an intermediate device 2 for supplying the melt with nozzles 3 with slotted holes 4, casting rolls 5 made in the form of high-temperature heat pipes that are connected with trunnions 6 and with a drive 7 with an adjustable speed, a regulation mechanism 8 the gap between the casting rolls 5. The mechanism 8 contains bearings 9 with thrust bearings 10, couplings 11 with rods 12, an electric motor 13. The installation contains a pair of side vertical walls 14 with inserts 15, a device 16 for heating the surface of the casting rolls 5, pyrometer 17, the electric regulator 18 of the flow of the cooling medium, thermocouples 19 with an automatic control system for the rolls 5, the hot chamber 20, the pulling rolls 21, the hot rolling stand 22, the secondary cooling zone 23, the scissors 24, the guide rollers 25, coilers 26. On the surface of the casting rolls 5, a coating 27 of heat-resistant steel is applied. In the upper part of the rolls there is a device 28 for monitoring the level of metal poured into the rolls. The casting roll 5 consists of a wall 29, an airtight cavity 30, a condenser 31 made in the form of a cup, inside which a pipe 32 is installed to drain the cooling medium, for example water, it is installed with a gap 33 in the condenser 31 using centering inserts 34, fine mesh 35 with a coolant (for example, alkali metals - sodium) 36, cover 37, manifold 38 for supplying a cooling medium with a seal 39, an electric regulator 18 of the flow of cooling medium.

Installation works as follows. Previously, before casting the metal into the casting rolls 5, devices 16 are turned on for heating their surface to a predetermined temperature controlled by the pyrometer 17. At the same time, the drive 7 of the rolls 5 is turned on through the trunnions 6. After reaching the set coating temperature of 27 rolls 5, the liquid metal feed control system is turned on from the intermediate ladle 1 through the intermediate device 2 with nozzles 3 with slotted holes 4 into the space between the casting rolls 5 and a pair of vertical walls 14 with stakes 15. The signal from device 28 that controls the level of the poured metal to rolls 5, in an automatic control system work roll 5 allows to harmonize the number of entering the casting metal rolls 5 at a rate producing a metal strip. The work of the casting roll 5, made in the form of a heat pipe, is as follows. Steel poured into the space between the rollers 5, leads to the heating of their walls 29 and, accordingly, of the coolant 38, partially retained on the grid 35 during rotation of the roll. After heating the wall 29 and the coolant 36 to a predetermined temperature, it boils with the formation of vapors that fill the sealed cavity 30. Turn on the supply of cooling medium to the manifold 38 through the regulator 18 of the flow of cooling medium, which then enters the gap 33 between the centering inserts 34, cools the surface the condenser 31, heats up and through the hole in the pipe 32 is removed from the roll. A thermocouple 13 installed in the pipe 22, allows you to record the temperature of the outgoing cooling medium. The coolant vapors 36 that fill the sealed cavity 30 condense on the outer surface of the condenser 31 and flow down the roll in the form of condensate. The heat generated during vapor condensation is transferred through the wall of the condenser 31 and is removed by the cooling medium. With an increase in the speed of obtaining a metal strip by an automatic control system for the operation of the rolls, the flow rate of the cooling medium increases through the electric regulator 18 of the flow rate of the cooling medium, the temperature of which is controlled by signals from the thermocouple 19.

If it is necessary to control the thickness of the tape leaving the rolls 5, the automatic roll control system activates the mechanism 8 for adjusting the clearance between the rolls 5. In this case, the electric motor 13 drives the couplings 11, and from them the rods 12, mounted in the thrust bearings 10, which transmit force through the bearings 9 on the trunnion 6 of the casting rolls 5, ensuring their simultaneous convergence or divergence. The metal strip emerging from the rolls 5, by means of pulling rolls 21, enters the hot chamber 20 with a controlled atmosphere, which eliminates the oxidation of the tape. Further supply of the metal strip to the hot rolling stand 22 ensures its plastic deformation with an increase in the mechanical characteristics of the metal.

Next, by pulling rolls 21, the metal tape is fed into the secondary cooling zone 23, where the temperature of the tape decreases. The cooled tape is cut on the scissors 24 and then through the guide rollers 25 it is twisted into a coiler 26.

Claims (2)

1. Installation for producing a continuous metal strip containing an intermediate ladle, an intermediate device for supplying melt through nozzles, casting rolls equipped with a pair of side vertical walls, a hot rolling mill, a cooling zone, guide rollers, winders, characterized in that it is equipped with casting rolls made in the form of high-temperature heat pipes with a coolant supply for cooling the rolls, a coolant flow controller and a thermocouple for measuring the temperature of the cooling medium food, a device for heating the surface of the casting rolls, a pyrometer for measuring the surface temperature of the rolls, a device for controlling the level of metal poured into the casting rolls, a mechanism for regulating the gap between the casting rolls and a system for automatically controlling the operation of the casting rolls, while the nozzles of the intermediate device are made in the form of nozzles from refractory material with slotted holes. 2. Installation according to claim 1, characterized in that the surface of the rolls is coated with heat-resistant steel with a thickness of δ, such that δ / R = 1/25 ÷ 1/20, where R is the radius of the roll.

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