EP0873804B1 - Method and apparatus for clamping of the wide sides of a continuous casting mould - Google Patents

Abstract

Clamping of the two broad-side walls (1) of a continuous casting mould, with the interposed narrow-side walls (20) by means of steel drawbars (4) in combination with adjusting elements such as screw connections, spring packages, wedges and hydraulic units. The drawbars take the form of bars with one smooth (40) and one screw-threaded (41) end, respectively with clamping elements (10) and nuts (42), and preferably also with spring packages (11, 14). The clamping elements and nuts are installed with a given clamping force and a preliminary tightness respectively.

Description

The invention relates to a device for bracing two opposing Broad side walls of a continuous casting mold with spaced in between Definition of the format width adjustable and preferably held clampable Narrow side walls, with tie rods made of their mutual bracing Steel are present and in cooperation with actuators on tension are feasible. The invention also relates to a method for bracing two opposite broad side walls of the mold.

A construction which is customary in the prior art is the fixing of the wide mold side walls using tie rods over disc springs using turnbuckles. In order to be able to adjust the narrow side walls, the spring tension must be For example, can be reduced with a complex hydraulic system, through which the clamping force of the narrow side walls is released.

The disadvantage here is the complex hydraulics and the risk of spring breakage, causing a decrease in the cohesion of the mold walls and a unintentional opening of the same is possible. Another disadvantage is the im cold start-up state already existing large contact pressure, which is due to the Thermal length change of the tie rods in the casting operation is reduced and thus to different tensions both in the tie rods and in the mold walls leads.

DE-OS 27 02 976 discloses a plate mold for the continuous casting of steel with a supporting frame and supported therein, provided with cooling devices, walls delimiting the mold cavity, at least one longitudinal wall is movable transversely to the mold axis and transverse walls, which consist of a holding plate, a support plate and a cooled copper plate exist between the Longitudinal walls can be clamped.

The technical requirement is that the transverse walls, their respective Support plate has wedge-shaped lugs on its upper and lower edge, wherein the lower nose engages in a wedge-shaped groove of the holding plate and the upper nose is attached to the holding plate with a clamping piece engaging behind this, can be clamped between the longitudinal walls by means of a spring clamping device are, and that to the Losseitenlängswand own hydraulic or mechanical acting device, which is supported against the supporting frame.

EP 0 107 564 discloses a mold for the continuous casting of objects rectangular cross section with two short sides that can be clamped between two long sides Plates that are clamped together in a support frame, whereby the long mold walls can be compressed by strong spring assemblies.

The technical requirement of this document is that the means for pressing of the long sides consist of pressing devices on two upper ones and lower levels of the mold are provided, and that separate, differently adjustable means for controlling the relief of the exercised Pressure by the upper pressure devices and by the lower pressure devices are provided. These devices exist for the upper and lower pressing each from at least a pair of cylinders, the hydraulically operated to release pressure by a control circuit, consisting from two separate lines for feeding the two pairs of cylinders, each line being provided with means for adjusting the pressure.

OS 27 42 742 discloses a device for adjusting one of the two face plates of a continuous casting mold with at least one elastic Element, which is supported on the face plate, and with one with the stationary scaffold connected mechanism, which the longitudinal displacement actuated a rod perpendicular to the face plate. The adjustment device also has at least one between this mechanism and the face Plate arranged working cylinder with which the elastic element can be compressed, the rod being fitted in such a way that it keeps the elastic element compressed when the loading of the working cylinder is interrupted.

From EP 0 417 504 A2 a continuous casting mold with two on a support frame is opposite arranged broad side walls known, between which Narrow side walls that can be slid against each other for format width adjustment are firmly clamped, with the tensioning between the broad side walls mechanical clamping elements are provided on the narrow side walls are in operative connection with hydraulic piston-cylinder units stand.

In this design, the support frames with their broad side walls are in the continuous casting mold so arranged and connected to the clamping elements that they both can be adjusted to each other as well as from each other. Here are the provide resilient tie rods at one end with a keyway into which when clamping the narrow side walls, a wedge is inserted, which has a Push rod and a swivel bearing with a hydraulic piston-cylinder unit is in operative connection.

A further mold design is known from document FR-A-2 356 467, at which tie rod with ends designed as pistons slidably inserted are. The piston ends of the tie rods are supported in the holes in the pillars embedded slidably against spring packs, while the columns themselves Base with enlarged diameter stored in cylindrical thickenings are formed in the movable plates of the frame, preferably one-story are. Both the fitting tolerances of the pistons in the bores and those from the bases in the bore of the cylindrical thickening of the plate as well as those of the rod in the axial bore of the column require extreme Degree of tolerance-compliant production. Such a known mold design is therefore complicated and technically complex.

Starting from the aforementioned prior art, the object of the invention based on an improvement in the known types of continuous casting molds in to bring about the sense that on the one hand the assembly and adjustability of the Chill narrow sides significantly simplified and damage on the other hand the mold in the event of faults, e.g. B. especially when excessive pressure peaks occur in the case of a thin slab hopper mold or a cold start-up line by adjusting the broadside clamping forces against the Narrow sides or avoided by the possibility of partially opening the mold becomes.

This object is achieved in a device for bracing two opposing ones Broad side walls of a continuous casting mold with spacing in between for the definition of the format width adjustable and preferably held clampable Narrow side walls, with tie rods for their mutual bracing made of steel and in cooperation with actuators for tension can be brought, solved in that the tie rods made of cylindrical rods with a threaded end with one, preferably with a spring assembly underlayable, screw connection and a smooth end with a Clamping element exist.

The spring assembly can be a mechanical or hydraulic spring assembly his. The hydraulic elements can be controlled or regulated.

Further expedient embodiments of the device are in accordance with the Subclaims provided.

The procedure for bracing the two opposite broad side walls A continuous casting mold is designed according to the invention such that as a tie rod Rods with only one threaded end are used, being on the opposite smooth ends of the through the Kokiilen broad side walls as well as the associated with them supporting frame insertable rods clamping elements put on and on the threaded nuts preferably with an intermediate layer each of a spring assembly are screwed on, and that the clamping elements with a predetermined clamping force and the nuts of the screw connections a predefined pre-tension can be set.

The method for bracing according to the invention results with great advantage the wide mold side walls an improvement of the known types of continuous casting molds in the sense that the clamping elements when exceeded can yield to the specified clamping force.

An embodiment of the method provides that that proportional to the clamping force Holding force of a clamping element according to the effective coefficient of static friction between tie rod and clamping element, for example Coefficients µ = 0.05 to 0.15 for steel / steel on smooth and dry surfaces, is designed according to the specification of a calculated clamping force so that they against the sum of all forces from the contact pressure of the mold broad side walls the narrow side walls plus the ferrostatic pressure forces and plus corresponds to a security surcharge.

Another embodiment of the method provides that the bracing the Koklllen broad side walls by tightening the screw connection, preferred using a torque wrench. In order to the clamping force of the broad side walls against the clamped between them Narrow side walls sensitive and exact with a given Clamping force can be set. The tension of the mold broad side walls is designed so that it a predetermined surface pressure of the contact surfaces the narrow side walls on the broad side walls plus that of the liquid Metal corresponds to ferrostatic forces.

Furthermore, the invention provides that the clamping force of the clamping element so it is specified that if the force exceeds the permissible sum Force increase of the mold broad side walls gives way to the clamping element and on Tie rod slides outwards. For this, a maximum permissible glide path of the Specified clamping element and an end stop on the tie rod, for example in the form an additional clamping element, arranged, this end stop preferred with the help of an alarm contact when the clamping element yields Triggers signals. This improves the security of the mold against damage, which is made possible for the first time with the help of the invention in that the Clamping elements only by frictional connection on the smooth ends of the tie rod held in place under load.

Figur 1

eine Kokille im Schnitt einer die Stützrahmen und Schmalseitenteile senkrecht schneidenden und mit den Achsen der Zugstangen verlaufenden Schnittebene,

Figur 2

ein Gewindeende eines Zugankers mit einer Stellmuttern aufweisenden Verschraubung unter Zwischenlage eines Federpaketes,

Figur 3

das glatte Ende des Zugankers gemäß Fig. 2 mit einem Klemmelement und Sicherungs-Endanschlag,

Figur 4

das Verspannungsprinzip der Erfindung.

Details, features and advantages of the invention result from the following explanation of an exemplary embodiment schematically illustrated in the drawings. Show it:

Figure 1

a mold in section of a sectional plane that perpendicularly cuts the support frame and narrow side parts and runs with the axes of the tie rods,

Figure 2

a threaded end of a tie rod with a screw connection having a nut with the interposition of a spring assembly,

Figure 3

2 with a clamping element and securing end stop,

Figure 4

the tension principle of the invention.

The sectional view of the mold according to Figure 1 shows the device according to the invention for bracing two opposite broad side walls 1 with the Tie rods 4. The cutting plane penetrates the narrow side parts 20 of the mold with adjusting devices 21 arranged therein for those in this sectional plane not visible narrow side walls. The tie rods 4 are resilient rods each with a smooth end 40 and a threaded end 41. On the smooth Ends 40 of those through the mold broad side walls 1 and through those assigned to them Support frame 3 or 3 'rods 4 which can be pushed through are on the one hand Clamping elements 10 plugged on, and on the threaded ends 41 are adjusting nuts 42 screwed with the interposition of a spring assembly 11, the whole way, that the Clamping elements 10 with a predetermined clamping force and the nuts 42 of the Screw connections 5 set with a predefined pre-tension become.

The clamping devices 10 fix the mold wide side walls 1 by frictional engagement with the smooth ends 40 of the tie rods 4, while the screw connections 5 at the opposite thread end 41 the tie rod 4 the prestressing of the mold broad side walls 1 against the narrow side walls with a defined force.

The broad side walls 1 are each on the support frame 3 of a fixed side and supported on the support frame 3 'of a loose side of the support frame and the tie rods 4 are through in these and in the broad side walls 1 existing guide openings 6 passed. On theirs protruding smooth ends 40 are the clamping elements 10 and the screw connections 5 under the protruding thread ends 41 Intermediate layer of plate spring assemblies 14 arranged; the spring packs can also be hydraulically controlled elements. These are in turn supported on the support frame 3.

For spreading the support frame 3 or 3 'with the wide side walls 1 on its loose and fixed side is a hydraulic unit 13 articulated between the tie rods 4, through which the support frame 3, 3 'together with the broad side walls 1, 1' opposite the Move the narrow side walls to an open position on each side to let.

Fig. 2 shows an enlarged view of the threaded end 41 Tie rod 4 with the adjusting nuts 42 of the screw connection 5 below Intermediate position of the plate spring assembly 14 or the controllable or regulable one Hydraulic element. The rod 4 penetrates the guide opening 6 in the support frame 3 and is with its threaded end 41, the Screw connection 5 and the plate spring assembly 14 from a closing element 18 surrounded and hermetically sealed. For example, corrosion of the screw 5 effective with simple means encountered.

3 shows the smooth end 40 opposite the threaded end 41 of the rod 4 with the clamping element 10 pushed on and fixed. This acts together with a number of radially arranged clamping wedges 9 which, under load from the spring assembly 11 with axial compressive stress, concentrically counter-wedge 8 against the rod 4 press. These counter wedges generate 8 concentric clamping forces K and thus a proportional adhesive force N according to the effective coefficient of static friction (µ) between rod 4 and clamping element 10. The adhesive force is, for example, at a coefficient of static friction µ between 0.05 and 0.15 for static friction against steel Steel designed for smooth and dry surfaces and specifying a calculable clamping force K so that it is the sum of all forces from the contact pressure A of the mold broad side walls 1 against the narrow side walls plus the ferrostatic pressure forces (D) and plus a safety margin (S) according to the formula Σ (A + D + S) = µ s x K = N equivalent.

The clamping device 10 is in contact with the clamping wedge 9 a hydraulic relief piston 16 which, when loaded with Hydraulic medium corresponding pressure through the supply channel 17 the Clamping tension of the spring assembly 11 overcomes and thus the counter wedge 8 relieved, so that the clamping element 10 from the smooth end 40 of the Rod 4 can be easily removed. Conversely, one depressurized state of the hydraulic medium of the piston 16 in the shown Stop position pushed back by the axial force of the spring assembly 11 and brought into a clamping position in relation to the clamping wedge 9, wherein the clamping element 10 is the pre-calculated clamping force K exercises against the smooth end 40 of the rod 4 and clamps.

In the example shown, the rod 4 is also by the Guide opening 6 of the support frame 3 passed through and through Attaching and clamping the clamping element 10 fixed.

As FIG. 3 further shows, each clamping element 10 can preferably on the rod of the tie rod 4 an end stop 12 with a predetermined Safety distance, preferably between 0.3 and 1.0 mm, assigned be the one (not shown) when in contact with the clamping element 10 Device for triggering a fault signal activated. This end stop 12, for example in the form of a on the smooth end 40th the rod 4 slidable thick disc can, for example Locking device 15 in the form of a locking screw in adjustable position.

Fig. 4 shows the tension principle according to the invention in a alternative bracing device, in which the clamping element 10 consists of two jaws 23, between which a rectangular shaped end 40 of a tie rod 4 clamped non-positively is and the clamping forces of a compression spring 19 and a plate spring assembly 22 are applied. The jaws 23 can also Have formations that have the round profile of a smooth end 40 partially enclose and clamp a tie rod 4. expansion screws 24 with screw head 25 and nut 26 connect the jaws 23rd

1 to 4 it can be seen that by Training the tie rod 4 as a rod with a smooth end 40 and a threaded end 41 an extremely simple assembly in the assembly the mold is made possible. By arranging the Clamping element 10 with a predetermined clamping force K is in the sense of a Slip clutch in the event of permissible load peaks being exceeded achieved additional security with uncomplicated means.

The invention thus optimally solves the problem set out at the beginning Task.

LIST OF REFERENCE NUMBERS

1

Wide side walls

3, 3 '

support frame

4

tie rods

5

screw

6

guide opening

7

tie rod

8th

counter wedge

9

clamping wedge

10

clamping element

11

Spring pack, mechanical or hydraulic

12

end stop

13

hydraulic power unit

14

Spring pack, mechanical or hydraulic

15

Locking device

16

Hydraulic relief piston

17

Hydraulic feed channel

18

terminating element

19

Coil spring, compression spring

20

Narrow side parts

21

Narrow-side adjusting

22

Belleville spring assembly

23

jaws

24

expansion screws

25

Screw head of 24

26

24 nut

40

Tie rod 4 smooth end

41

Thread end of the tie rod 4

42

adjusting nut

43

Rectangular profile of 40

Claims (14)

1. A device for clamping two opposing wide sides (1) of a continuous casting mold, having narrow sides, whose interval is adjustable for fixing the format width and which can preferably be clamped, in between them, with tie rods (4) made of steel being present for their mutual clamping and able to be brought into tension by cooperating with adjustment elements,
   characterized in that
   the tie rods (4) consist of cylindrical rods having a threaded end (41) with a screw connection (5), which can preferably have a spring assembly (14) placed under it, and a smooth end (40) having a clamping element (10).
2. The device according to claim 1,
   characterized in that
   the wide sides (1) press against supporting frames (3) and the tie rods (4) are inserted through guide openings (6) present in the supporting frames and in the wide sides (1) and the clamping elements (10) are located on the projecting smooth ends (40) of the tie rods and the screw connections (5) are located on the threaded ends (41) of the tie rods, with disc spring assemblies (14) being interposed, and the tie rods press against the supporting frame (3).
3. The device according to claim 1 or 2,
   characterized in that
   a hydraulic assembly (13) for spreading the supporting frame (3) with the wide sides (1) on each of its loose and fixed sides is coupled between the tie rods (4), through which the supporting frame (3), together with the wide sides (1, 1'), can be displaced relative to the narrow sides in every direction into an open position.
4. The device according to claim 1, 2, or 3,
   characterized in that
   the clamping elements (10) cooperate with clamping wedges (9) which are each supported by a spring assembly (14) with a preset and preferably adjustable clamping force.
5. The device according to one or more of the claims 1 to 4,
   characterized in that
   each clamping element (10) is assigned an end stop (12) on the rod of the tie rod (4) at a preset safety distance, preferably between 0.3 and 1.0 mm, which activates a device for triggering a signal when it comes into contact with the clamping element (10).
6. The device according to one or more the claims 1 to 5,
   characterized in that
   the clamping element (10) consists of an arrangement of clamping jaws acting on the rod of the tie rod (4) by means of coil springs and/or pressure springs (19) and a disc spring assembly (11).
7. The device according to claim 6,
   characterized in that
   the smooth ends (40) of the tie rods (4) have a round profile or a rectangular profile (43).
8. A method for clamping two opposing wide sides (1) of a continuous casting mold, having narrow sides, whose interval is adjustable for fixing the format width and which can preferably be clamped, in between them, with tie rods (4) made of steel being used for their mutual clamping and able to be brought into tension or loosened to adjust the narrow sides by cooperating with adjustment elements such as screw connections and spring assemblies, wedges, or hydraulic assemblies according to claim 1,
   characterized in that
   rods with only one threaded end (41) are used as tie rods (4), with clamping elements (10) being pushed onto the opposing smooth ends (40) of the rods (4), which can be inserted through the mold wide sides (1) and the supporting frame (3) assigned to them, and nuts (42) being screwed onto the threaded ends (41), preferably with a spring assembly (14) being interposed in each case, and the clamping elements (10) are set with a preset clamping force and the nuts (42) of the screw connections (5) are set with a defined, preset pretension.
9. The device according to claim 8,
   characterized in that
   the adhesion force (N) proportional to the clamping force (K) of a clamping element (10) is designed corresponding to the effective coefficient of adhesion (µ) between rod (4) and clamping element (10), for example at a coefficient µ = 0.05 to 0.15 for steel/steel with smooth and dry surfaces, according to the specification of a clamping force (R) determined by computer, in such a way that it corresponds to the sum (Y-) of all forces from the contact force (A) of the mold wide sides (1) against the narrow sides plus the ferrostatic pressure forces (D) and plus a safety margin (S), according to the formula: Σ(A + D + S) = µ s x K = N
10. The method according to claim 8 or 9,
    characterized in that
    the pretensioning of the mold wide sides (1) is performed by tightening the screw connection (5) in a way limited by torque.
11. The method according to claim 8, 9, or 10,
    characterized in that
    the pretensioning of the mold wide sides (1) is designed in such a way that it corresponds to a preset contact pressure of the contact surfaces of the narrow sides on the wide sides (1) plus the ferrostatic forces exercised by the liquid metal.
12. The method according to one or more of the claims 8 to 11,
    characterized in that
    the clamping force (R) of the clamping element (10) is preset in such a way that if the force on the mold wide sides (1) exceeds the permissible sum (Σ) of the forces (A + D + S), the clamping element (10) yields and slides outward on the tie rod (4).
13. The method according to one or more of the claims 8 to 12,
    characterized in that
    a maximum permissible slide path of the clamping element (10) is preset and, for this purpose, an end stop (12), in, for example, the form of an additional clamping element, is located on the tie rod (4), and the end stop triggers a signal, preferably with the aid of an alarm contact, if the clamping element (10) yields.
14. The method according to one or more the claims 8 to 13,
    characterized in that
    the clamping elements (10) are held in their position under load on the smooth ends (40) of the tie rods (4) exclusively by frictional connection.

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