KR19990067275A - Method and apparatus for inducing billet in continuous casting equipment - Google Patents

Abstract

The present invention relates to a method for inducing billets in a continuous casting plant, in particular in a plant for producing thin slabs from steel, said plant having a billet induction frame with a mold and a cooling device. The billet is deprived of heat indirectly after leaving the mold. The billet is retained in shape, at least in cross section, through the gaseous medium, is guided in the drawing direction of the billet and further cooled. The billet is also moved through the billet induction frame at a predetermined speed in a manner defined by mechanical means. At this time, the billet is accelerated or braked. The invention also relates to an apparatus for carrying out the method.

Description

Method and apparatus for inducing billet in continuous casting equipment

In continuous casting equipment of slab or cog bloom, the billet is regularly guided by rollers arranged under the mold. The rollers have an inner diameter of at least approximately 100 mm if not cooled and at least approximately 140 mm if internally cooled. Slab-continuous casting installations with slab widths up to 3.5 m use separate rollers with intermediate bearings.

Spray cooling is used regularly when using rollers that are not cooled. The jet cooling carries the risk of uncontrolled billet cooling resulting in cracking of the billet surface.

The inner diameter of the roller and the width of the slab together determine the spacing of the individual rollers. The spacing of the rollers, which can be regarded as the size characterizing the support of the billet and the bulging of the billet, directly affects the quality of the billet. The bulging of the billet is determined by the casting speed and the spacing of the rollers. A standard slab with a thickness of approximately 200 mm has a casting speed of 2.2 m / min, while a thin slab with a thickness of approximately 50 mm has a casting speed of 6 m / min, with a casting speed of 8 m / min.

In addition, billet shells of thin slabs are much hotter in the same metallurgical position than billet shells of standard slabs until they flow out of the mold and solidify.

Since not only the diameter of the rollers but also the intervals of the individual rollers can not be reduced arbitrarily, the billet bulges when the casting speed is relatively fast and the casting thickness is relatively thin, thereby accelerating the tendency to damage, but not so remarkable. not.

Plates are disclosed as billet guide members in addition to billet guide rollers. EP 0 107 563 A1 shows a grid arranged under the mold. The empty space of the lattice impinges coolant, for example spray water, on the billet surface.

A disadvantage of the members is that a large friction force is generated between the billet and the plates. In addition, there is a risk of quality vulnerabilities in the form of breakage and explosion by confined water. In addition, the drawing of the billet requires a large tensile force causing a large load on the billet shell.

The present invention relates to a method for inducing a billet in a continuous casting facility, in particular a facility for producing thin slabs from steel, the apparatus comprising a billet induction frame equipped with a stationary mold or a moving mold and a cooling device. Have The invention also relates to an apparatus for carrying out the method.

1 is a view of a continuous casting device.

2 is a cross-sectional view of the continuous casting device.

3 is a plate segment having a partition wall of a concave surface;

4 is a plate segment of a pipe arranged in a maze.

It is therefore an object of the present invention to create a guide using a simple means for a fast casting speed which has a structurally simple means and makes a billet less wearable to enable a high quality surface.

The invention is achieved by features that characterize claim 1 of the method and claim 5 of the apparatus.

In the present invention, the billet slides over a gas cushion positioned between the plate segments and the billet after leaving the mold. The billets are indirectly deprived of heat as cold plates that do not contact the billets receive radiant heat. In addition to maintaining the shape of the billet through the suitable structure of the plate segments on the partition wall in the billet direction, leading to billet drawing direction, and receiving indirect heat (radiation) by the cold plates Nitrogen cooled by vi) is preferably used as the gas medium.

In bow-shaped installations the billets are bent by a number of bend points or continuously squeezed by monotonous curves. The work that can be performed by each of the segments and the gas flim of the series of segments consists of the following items:

Support of the billet as a function of weight ratio depending on the position of the billet induction part between the vertical part and the horizontal part of the continuous casting induction part;

-Balancing of ferro static pressure as a function of the vertical gap with the meniscus

-Bending and Orientation of Billets

-Reduction of billet thickness during casting rolling and solidification

-Transfer of billet

It should also be taken into account that the top of the billet-inducing plate segments need not carry out any work to accommodate the billet (weight). In addition, the special operations vary in each segment or by the metallurgical length from the mold outlet to the end of the billet guide.

Different functions for each plate segment are stabilized by pressure times mass by the inherent structure and / or control of the gas medium. This requires special consideration of the dependence of the billet's shell thickness. When designing the plant, the hydraulic action acting on the billet is measured so that the billet is guided, transported, and-if desired-reduced to casting thickness but compressed in a controlled state, ie damaged by undesirable bulging. Be careful.

At the same time the billet is moved through the billet induction frame at a predetermined speed in a manner defined by mechanical means (here substantially continuous casting rollers). The rollers can assist, charge or stabilize the conveying or desired casting speed and / or bending and direction adjustment processes. In order to ensure the stability of the casting speed, a roller arranged at the distal end of the continuous casting frame is used. Because here the billet is completely solidified.

The drive energies by the gas flow and continuous casting rollers can be arbitrarily adapted to each other's energy. In a preferred form of the invention, the billet is conveyed by gas flow and braked at standard speed at the rate of gas flow by the continuous casting rollers.

The plate segments consist essentially of a hollow body which preferably draws in coolant. In the plate segments, a net is formed of distribution conduits on a surface inclined toward the billet. The distribution conduits carry a gas, for example nitrogen. The cross sections of the distribution conduits are connected to each other and the integrated conduits are connected to the gas delivery station. Individual nozzle openings of the distribution conduits may be formed in various ways. Their distribution is also adjusted correspondingly to the operating energy at their position in the induction section. Thus, for example, the number of nozzles and / or the number of nozzle openings is varied as a function of metallurgical length and width in the segment. This is to perform different tasks at different geometric positions when the pressure supply is the same. The nozzles may be distributed not only horizontally but also vertically in the casting direction for each pressure system (segment plate, pneumatic cushion), for example, in the same pressure in the sense that the performance is different. One segment can also be followed by different and independent pneumatic systems.

The nozzles or portions of the nozzles are also placed in a casting direction at an acute angle of inclination. This is to assist the transfer of the billet. Billet feed assistance stabilizes and assists the casting speed and reduces the expenditure of work of the roller pairs arranged between the plate segments. The plate segments are spaced from the billet surface at least at the edge to allow gaseous defined leakage between the billet and at least the lip arranged at the edge.

The plate segments are connected to actuators, for example piston-cylinder-units. With the piston-cylinder-units the gap between the plate segment and the billet and the resulting gas leakage can be regulated.

The partition wall inclined toward the billet is formed to discharge a maximum of radiant heat in form and material. In this case, copper having a relatively thin partition thickness is preferably used to receive heat through the cooling water in the cooling case of the plate segment.

In another form of the invention, the thickness of the partition wall of the plate segment inclined toward the billet is modified. In detail, the thickness decreases toward the major axis of the plate. The partition wall of the segment inclined towards the billet may also be coated with a wear resistant protective layer, for example nickel and / or chromium.

In one form, the plate segment consists of pipes arranged in a maze, and distribution conduits for supplying gas to their tangents are inserted. The pipe conduit can speed up the cooling water, thus dissipating as much radiant heat as possible from the billet.

In order to ensure stable center operation of the billet, a recess is formed in the partition wall of the plate segments inclined toward the billet in the billet conveyance direction. The size of the concave surface of the bulkhead starts at the concave mold and passes through all segments of the billet induction part from the first segment to a shallow concave or flat surface, for example, to the distal end of the billet induction frame or to the complete solidification state of the billet. Is reduced. In this way parallel slabs or slabs having a profile of the desired concave surface can be produced.

Pneumatic working profiles can also be defined by, for example, different hole sizes in the width of the segment. Thus, for example, it is preferable that the pneumatic action is relatively small in order for the membrane action of the billet to be suitable in the middle of the plate segment. The billet is more durable at the edges, ie at the corners, than at this middle.

In addition, if the thickness of the billet is predetermined, the pneumatic action charged in can be reduced or increased when the pressure is equal by the opening or the closure of the plate segments. The pneumatic action value may be predetermined by the spacing of the upper or lower plate segments when the thickness of the slab is predetermined.

Substantially in the device according to the invention the billet is conveyed pneumatically by a continuous casting machine at the desired casting speed. The motors of the continuous casting rollers are responsible for stabilizing at the correct standard casting speed through further work. The feed (motor drive) or rollers move when the generator is driven to brake the slab at the desired standard speed. If the flow by the motor exceeds the predetermined limit, the basic speed is corrected by air pressure.

With the methods and apparatus presented above, the following are achieved:

The billet is not bulged even when the casting speed is up to 10 m / min and is therefore not damaged;

The billet does not require direct water cooling, thereby minimizing energy consumption,

To prevent oxidation of the billet when using an inert gas,

-Can be stepped and adjusted with minimal area ratio damage;

During the solidification process it is possible to achieve a step casting and thereby reduce the thickness of the billet,

-There is no rotating mechanical member and has the following advantages

○ This allows for minimal wear of the machine,

○ Casting stability is higher than that of cooled so-called lattice jets,

No mechanical constraints are seen in the transfer of the billet, for example in the case of continuous casting guide frames consisting of rollers and especially in very large slab installations, especially thin slab installations, which cast quickly.

Embodiments of the invention are shown in the accompanying drawings.

1 shows a continuous casting apparatus having a tundish 11, from which the liquid metal is led into the mold 12 through the dip tube 13. In this case, the continuous casting device is a bow-shaped continuous casting facility for producing the slab B. In the continuous casting plant, the billet is drawn from the mold 12 facing vertically while surrounded by billet shell W. Under the mold 12 there are rollers 21. The rollers are driven by a roller driver 22 and form a guide with plates 30 consisting of individual plate segments 31. The plate segments 31 are arranged above and below the slab B. The rollers 21 are arranged between the individual plate segments 31.

The roller drivers 22 are also connected to the measuring and adjusting device 23.

The housing 61 surrounds the rollers 21 and the plate segments 31 which guide and transport the billet. The housing 61 is connected to the gas cooler 64 and the gas purifier 65 through conduits 62 for the induction of gas and conduits 63 for the induction of gas. Gas delivery station 49 is formed in gas conduit 62. The gas is transported by the gas conveying station through the gas conduits 46 to the individual plate segments 31.

For cooling of the individual plate segments 31, coolant is sucked through the feed conduit 72 through the pump 71 and supplied to the individual plate segments 31 and back drawn through the back feed conduit 73.

FIG. 2 shows a sectional view of a continuous casting apparatus having the housing surrounding the plate segments 31 and the slab B. FIG.

The plate segments 31 are adjustablely fixed to the piston cylinder device 51 for maintaining the spacing of the plates.

Coolant is supplied to the plate segments 31 by the conduit 72 and back drawn by the conduit 73.

The gas exits the outlet 42 by the integrated conduit 46 and the distribution conduit 45 in the outer zone, the distribution conduit 43 for the supply in the intermediate zone and also by the distribution conduits 44 for the supply of the interstitial zone for gas supply. Is conveyed into the intermediate chamber between the plate segments 31 and the slab B. The plate segments 31 have a partition 32 which can represent a lip 34 on the inclined surface of the slab.

The slab B has a billet shell W, in which there is a crater S of a liquid metal.

3 shows another cross-sectional view A-A of the plate segments 31, wherein the partition wall 32 inclined toward the slab B is formed as a concave surface. In the upper part of the figure, the partition wall 32 is formed as a double wall, wherein the plate 35 arranged directly on the slab B is made of a material having high thermal conductivity, for example, copper. The copper plate 35 may then be coated with a wear resistant layer 36, for example nickel or chromium.

The partition 32 represents a lip 34 at the edge of the top of the figure. The partition wall thickness d of the partition wall 32 may be formed to become thicker from the middle area toward the edge.

The distribution conduit 43 and hole 41 supply gas to the outlets 42.

The slab B has the billet shell W, the billet shell surrounds the crater S. The slab B represents reboring in the middle region.

One plate segment 31 is shown in FIG. 4, which consists of a pipe 38 arranged in a maze, which is connected with a supply conduit 72 and a back feed conduit 73. At tangent 39, the distribution conduits 43, 44, 45 immediately end on the inclined side towards the slab B.

At the bottom of the figure a cross section B-B is shown, wherein the pipes are hermetically connected at the tangent 39 and indirectly contact only when the distribution conduits 43, 44 and 45 are worn. The outlets 42 of the distribution conduits appear in the space between the plate segment 31 and the slab B.

Location list

Continuous casting mold

11 tundish

12 template

13 Immersion Pipe

Billet Induction Frame

21 rollers

22 roller drive

23 Measurement and Control

30 plates

31 plate segment

32 bulkhead

33 middle carton

34 edge lip

35 copper plates

36 Wear Resistant Layer

38 labyrinth pipes

39 tangents

Gas supply

41 holes

Exit 42

43 intermediate distribution conduits

Distribution conduit between 44

45 external distribution conduit

46 Supply Integration Conduit

49 Air Transport Station

Spacing of plates

51 means, piston cylinder unit

cover

61 housing

62 forward conduit

63 reverse conduit

64 gas chiller

65 Purifier

Water cooling

71 pumps

72 supply conduit

73 Reverse Supply Conduit

74 Chilled water reservoir

B slab

S crater

W Billet Shell

d bulkhead thickness

Claims (20)

In a continuous casting facility having a mold and a billet induction frame equipped with a cooling device, in particular a method for inducing billets in a facility for producing thin slabs from steel, The billet is indirectly deprived of heat after leaving the mold and at least by the gas medium -Keep the shape -Induced in the billet feed direction -Additional cooling And the billet is moved through the billet inducing frame at a predetermined speed in a manner defined by mechanical means, wherein the billet is accelerated or braked. The method of claim 1, wherein the gaseous medium is presumably adjustable in accordance with the thickness of the billet shell with respect to mass and pressure. The method of claim 1 or 2, wherein the gas flow is directed over the billet surface to affect the casting speed. The method of claim 1 wherein the thickness of the billet is reduced at the mold outlet of at least one plate segment. For carrying out the method according to claim 1, a billet induction frame having rollers and plates with holes across the surface of the billet has a mold running in the casting direction and parts for cooling the billet surface. In continuous casting apparatus for producing thin slabs from billets, especially steel, The plates 30 are divided into segments 31, with rollers 21 formed between the segments, In the plate segments 31, a net formed of distribution conduits 43, 44, and 45 is formed on a surface inclined toward the billet B, and a gas medium may be supplied by the distribution conduits, The cross sections of the distribution conduits 43, 44, 45 are connected to each other and are connected to the gas transport station 49 by the integrated conduits 45, The plate segments (31) are arranged at least at intervals with the billet surface at the edges (34), the spacing permits limited leakage of the gaseous medium. 6. The plate segment (31) according to claim 5, wherein the outlets (42) of the distribution conduits (43, 44, 45) are inclined toward the billet (B) at an angle inclined in the conveying direction of the billet (B). Continuous casting apparatus, characterized in that the charge into the partition (32) of. The continuous casting apparatus according to claim 6, wherein the partition wall (32) inclined toward the billet (B) is formed so as to transport the radiant heat to the maximum from the billet shell (W) in shape and material. 8. A continuous casting apparatus according to claim 7, characterized by coating on the partition wall (32) inclined toward the billet (B) with a wear resistant layer, for example nickel and / or chromium. 5. The plate segments (31) according to claim 4, wherein the plate segments (31) consist of pipes (38) through which coolant flows, arranged in a maze, and at the tangents (39) of the pipes (43). , 45) is a continuous casting device, characterized in that formed perpendicular to the pipe intermittent (導 桿). 6. A continuous casting apparatus according to claim 5, characterized in that means (51) are formed for modifying the spacings of said plates independently of one another with respect to said billet (B). 6. The plate segments (31) according to claim 5, characterized in that the plate segments (31) are formed with cushions, and the plate segments exhibit a lip (34) which affects the gas medium and heat loss from the slab (B) at the edges. Continuous casting device. 12. The continuous casting apparatus according to claim 11, wherein the thickness (d) of the partition walls (32) of the plate segments (31) is reduced toward the major axis of the plate. 6. The continuous casting apparatus according to claim 5, wherein the partition wall (32) inclined toward the billet (B) of the plate segments (31) is formed as a concave surface in the billet (B) conveying direction. 14. The continuous as claimed in claim 13, wherein the size of the concave surface of the partition wall 32 is reduced in the conveying direction of the billet B so as to be in a zero state at the end of the billet induction frame representing the plate segments 31. Casting equipment. 11. Apparatus according to claim 14 or 10, characterized in that the means (51) are pneumatic actuators formed at the first position of the first plate segment 31 after the mold (12). 6. The continuous as claimed in claim 5, wherein the number of distribution conduits (43, 44, 45) in the plate segments (31) is deformed as a function of metallurgical length in consideration of the membrane action of billet shell thickness. Casting equipment. 6. The inner diameter of the distribution conduits (43, 44, 45) in the plate segment (31) according to claim 5 is a metallurgical length for carrying out a predetermined work according to the geometric position of the plate segment when the pressure is supplied equally. Continuous casting apparatus, characterized in that controlled by the function of. 6. The rollers (21) according to claim 5, wherein the rollers (21) arranged between the plate segments (31) are connected to an adjustable roller driver (22), by which the rotational speed and tension of the rollers can be adjusted. Continuous casting apparatus characterized in that there is. In the preceding claims, the plate segments 31, the rollers 21 and the billets B are connected to the gas cooler 64 and the purifier 65 by conduit systems 62, 62. Continuous casting device characterized in that it is surrounded by a housing (61) connected with. 20. A continuous casting apparatus according to claim 19, wherein the conduit system (62, 63) is formed so that gas, for example nitrogen, can be supplied to the compressor again after it has been purified and cooled.