EP3013499B1 - Two-dimensional oscillation of a continuous casting mould - Google Patents

Description

Field of engineering

The present invention relates to a method and a device for oscillating a mold of a continuous casting machine (also called continuous casting mold).

On the one hand, the invention relates to a method for oscillating a mold of a continuous casting machine, wherein the mold comprises two narrow side and two wide side plates, and the mold oscillates in the vertical direction relative to a stationary support structure with a first frequency f _V.

• die Kokille mit einem im Wesentlichen rechteckigen Formhohlraum, wobei die Kokille zwei Schmalseitenplatten und zwei Breitseitenplatten umfasst; und
• eine erste Oszillationseinrichtung zur Oszillation der Kokille gegenüber einer ortsfesten Stützkonstruktion in vertikaler Richtung.

On the other hand, the invention relates to a device for oscillating a mold of a continuous casting machine, comprising

• the mold having a substantially rectangular mold cavity, the mold comprising two narrow side plates and two wide side plates; and
• a first oscillation device for oscillation of the mold relative to a stationary support structure in the vertical direction.

State of the art

In continuous casting, it has long been known to oscillate a mold one-dimensionally in a vertical direction relative to a stationary support structure. On the one hand, the forming in the mold strand is lubricated by the discontinued on the liquid steel casting powder; On the other hand, the adhesion of the strand to a copper plate of the mold is prevented. Due to the one-dimensional oscillation of the mold, the strand has so-called oscillation marks, the strand quality due to transverse cracks, casting powder, locally changed heat dissipation or unfavorable microstructure negatively influence. It is further known that the continuous casting process or the quality of the strand can be improved by the use of optimized casting powders or by optimized parameters of the mold oscillation (amplitude, frequency, sinusoidal or non-sinusoidal curve shape).

From the JP 2000042691A It is also known to set a wide side plate of a slab mold in a circular or elliptical vibration. The disadvantage of this is that the broadside plate oscillates at a relatively high frequency (equal to the frequency of the oscillation in the vertical direction), and that in the case of the circular oscillation, the amplitudes for the vertical and the horizontal oscillation must be the same. Furthermore, the length of the locus is relatively short. Due to the high complexity, the method or device is difficult to use in practice.

The US 5579824 A shows a method for oscillating a mold of a continuous casting machine, wherein the broad side plates 1 oscillate in the broadest sense in the horizontal direction.

From the WO2005 / 009638 A1 For example, a method for producing a magnesium tape is known. The mold used oscillates in the vertical and horizontal directions.

Finally, out of the DE 19718235 A1 a mold with a broad side wall, in which the upper portion of the broad side wall can be driven in an oscillating manner.

Summary of the invention

The object of the invention is to overcome the disadvantages of the prior art and a method and a To represent apparatus for oscillating a mold of a continuous casting machine, with which the strand is better lubricated by the casting powder and the strand has fewer oscillation marks. In addition, the device according to the invention should be simpler than known devices for a two-dimensional oscillation.

This object is achieved in the aforementioned method in that at least one broad side plate (preferably both wide side plates) of the mold oscillates horizontally in the width direction of the broadside plate at a second frequency f _H , where f _V ≠ f _H , and that for all points of the locus of the Wide side plate the amount | v | the speed is greater than 0.

In the evaluation of two-dimensional oscillation patterns (locus curves), it has surprisingly been found that it is particularly favorable when the frequencies for the oscillations in the vertical and horizontal directions are different. As a result, the length of the locus is extended at an oscillation cycle, which has a very positive effect on the lubricating effect of the casting powder. In addition, the strand and the broadside plate are loaded very evenly. In addition, it is very favorable if the locus of the broad side plate of the mold does not have any dead centers (ie points for which the magnitude of the speed is equal to zero, ie l v l ≡ 0). As a result, a direction reversal of the broadside plate is prevented.

In a two-dimensional oscillation, the amount of speed is calculated v with the velocity components v _H in the horizontal direction and v _V in the vertical direction through $\left|\overrightarrow{v}\right|=\sqrt{{\mathrm{<figure-callout\; id="2"\; label="v\; H"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">v\; </figure-callout>}}_H^{}+{\mathrm{<figure-callout\; id="2"\; label="v\; V"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">v\; </figure-callout>}}_V^{}}\mathrm{,}$

• die erste Frequenz f_V ist ein ganzzahliges Vielfaches der zweiten Frequenz f_H, f_V = n. f_H mit n ∈ {2,3,4,5...} oder
• die zweite Frequenz f_H ist ein ganzzahliges Vielfaches der erste Frequenz f_V, f_H = n . f_V mit n ∈ {2,3,4, 5...}.

Simple synchronization between the vibrations in the horizontal and vertical directions is possible, if applicable

• the first frequency f _V is an integer multiple of the second frequency f _H , f _V = n. f _H with n ∈ {2,3,4,5 ...} or
• the second frequency f _H is an integer multiple of the first frequency f _V , f _H = n. f _V with n ∈ {2,3,4, 5 ...}.

In this case, a broad side plate of the mold is oscillated in the vertical direction with the first frequency f _V , which is either an integer multiple of the second frequency of the horizontal oscillation f _H (eg, two, three, four times, etc.), or at the second frequency f _{H is} an integer multiple of the first frequency of the vertical oscillation f _V.

• die erste Frequenz f_V ist kein ganzzahliges Vielfaches der zweiten Frequenz f_H, f_V ≠ n. f_H mit n ∈ {2,3,4,5...}, oder
• die zweite Frequenz f_H ist kein ganzzahliges Vielfaches der ersten Frequenz f_V, f_H ≠ n. f_V mit n ∈ {2,3,4,5...}.

The greatest possible length of the locus during an oscillation cycle is achieved, if applicable

• the first frequency f _V is not an integer multiple of the second frequency f _H , f _V ≠ n. f _H with n ∈ {2,3,4,5 ...}, or
• the second frequency f _H is not an integer multiple of the first frequency f _V , f _H ≠ n. f _V with n ∈ {2,3,4,5 ...}.

In addition to the oscillation of the entire mold (including the wide side plates) in the vertical direction, according to the present invention, at least one wide side plate, preferably both wide side plates, of the mold is oscillated horizontally in the width direction of the wide side plate (ie, in the width direction of the strand, the width direction being normal to the casting direction and thickness direction). By restricting that for all points of the locus of the broadside plate the amount of velocity is> 0, | v | > 0, it ensures that the trajectory of the broadside plate is smooth and has no dead spots. As a result, the direction reversal of the mold, which is particularly stressful for the lubrication of the strand, is avoided. Thus, with the same quality of the casting powder, a more efficient lubrication of the strand can be achieved. On the other hand, in the method according to the invention with the same lubricating effect, the casting speed - and thus the productivity - can be increased.

Since the frequency of the oscillation is cubic in the power consumption, the power consumption for the horizontal oscillation is particularly low when the first frequency f _{V is} greater than the second frequency f _H , ie f _V > f _H.

Additionally or alternatively, it is favorable if the amplitude of the vertical oscillation is greater than or equal to the amplitude of the horizontal oscillation. This can also reduce the energy consumption for the horizontal oscillation.

In order to prevent a "tumbling" of the mold, it is advantageous if the two broad side plates of the mold oscillate in opposite directions, ie have a phase difference of substantially 180 °. Due to the opposite movements of the mass balance of the mold is improved.

Of course, it is also possible that the two broad side plates of the mold oscillate in the same direction, i. have a phase difference of substantially 0 °.

In principle, it does not matter whether the method according to the invention is used in a straight or a curved mold. Furthermore, the method is not limited to vertically oscillating molds; Rather, it could also be used for horizontally oscillating molds (so-called horizontal systems).

The object of the invention is also achieved by the device mentioned, wherein a second oscillation means for oscillation of at least one broad side plate of the mold is provided opposite the adjacent narrow side plates in the horizontal direction, and the wide side plate is slidably formed with respect to the adjacent narrow side plates.

Since the derivation of a harmonic oscillation again represents a harmonic oscillation, a smooth locus for the broadside plate is achieved when the broadside plate horizontally oscillates horizontally in the width direction of the broadside plate. It is particularly preferred if the vertical oscillation is also harmonious.

In addition to the first oscillating device for the oscillation of the mold in the vertical direction, the device according to the invention has at least one second oscillating device for horizontally oscillating at least one broad side plate of the mold relative to the adjacent narrow side plates in the width direction of the broad side plate. By the oscillation of the mold in vertical and horizontal direction is improved at the same casting speed, the lubricating effect of the casting powder on the strand.

It is advantageous if each of the two wide side plates is assigned its own second oscillation device for horizontal oscillation in the width direction. As a result, the mass balance of the mold can be improved.

In order to reduce the energy consumption for the oscillation of the mold in the vertical direction, it is advantageous if the first oscillating device has at least a first elastic element and a first oscillation drive, wherein the first elastic element and the first oscillation drive each with the mold and the stationary support structure are connected.

A simple construction for the second oscillating device results when the mold comprises a mold frame and the second oscillation device comprises a second oscillation drive, wherein the second oscillation drive is connected on the one hand to the vertically oscillating mold frame and the broad side plate.

The power consumption for the horizontal oscillation of the wide side plates can be reduced when a second elastic member is disposed between the mold frame and the wide side plate, and the wide side plate can be offset from the vertically oscillating mold frame by the second oscillation drive in a horizontal oscillation in the width direction.

It is expedient here if the second elastic element is a spring band or a helical spring.

In particular, for smaller strand formats (billet or billet formats), it is advantageous if a first and / or a second oscillation drive is a linear electric motor. Due to the high power density, it is advantageous if the electric linear motor is a piezoelectric actuator.

For larger formats, it is expedient if a first and / or a second oscillation drive is a hydraulic linear motor, such as a hydraulic cylinder.

In order to keep the friction and thus the energy consumption for the horizontal oscillation low, it is advantageous if the broadside and the adjoining narrow side plates have sliding surfaces, preferably of sintered metal, which allow a relative movement.

The friction and the energy consumption for the horizontal oscillation can also be kept low, when the first wide side plate with the fixed side and the second wide side plate are connected to the loose side of the Kokillenrahmens, the Losseite is connected via a hydraulic clamping unit with the fixed side, and preferably the Clamping force of the clamping unit, particularly preferably hydraulically adjustable. Here, the clamping force can be e.g. hydraulically by means of the loading of the clamping unit by different high hydraulic pressures, easily adjusted.

Brief description of the drawings

• Fig 1 eine Darstellung einer nicht erfindungsgemäßen Bewegungsbahn einer Breitseitenplatte bei einer eindimensionalen (1 D) Oszillation
• Fig 2a,2b je eine Darstellung einer nicht erfindungsgemäßen Bewegungsbahn einer Breitseitenplatte bei einer zweidimensionalen Oszillation
• Fig 3-4 je eine Darstellung einer Variante der erfindungsgemäßen Bewegungsbahn einer Breitseitenplatte bei einer zweidimensionalen Oszillation
• Fig 5-8 verschiedene perspektivische Darstellungen (Fig 5 von schräg oben; Fig 6 von schräg unten; Fig 7 ohne die Losseite des Kokillenrahmens; und Fig 8 mit einer Detailansicht der Oszillationseinrichtung für eine Breitseite der Kokille) einer Ausführungsform einer erfindungsgemäßen Vorrichtung zur zweidimensionalen Oszillation der Kokille.

Further advantages and features of the present invention will become apparent from the following description of non-limiting embodiments. The figures show:

• Fig. 1 a representation of a non-inventive trajectory of a broadside plate in a one-dimensional (1 D) oscillation
• 2a, 2b in each case a representation of a non-inventive movement path of a broadside plate in a two-dimensional oscillation
• Fig 3-4 in each case a representation of a variant of the movement path according to the invention of a broadside plate in a two-dimensional oscillation
• Fig. 5-8 various perspective views ( Fig. 5 from diagonally above; Fig. 6 from diagonally below; Fig. 7 without the lot side of the mold frame; and Fig. 8 with a detailed view of the oscillation device for a broad side of the mold) of an embodiment of a device according to the invention for the two-dimensional oscillation of the mold.

Description of the embodiments

In Fig. 1 is a locus (also called movement path) for a broad side of a vertically oscillating mold according to the prior art in a one-dimensional oscillation. From the locus, it is immediately apparent that the direction of movement of the mold - and thus also of the broad side plate - reverses at top dead center OT and bottom dead center UT, respectively; Furthermore, for the velocity v of the mold in the two dead centers OT and UT v ≡ 0. In addition, the acceleration of the mold at the dead centers OT and UT has just a maximum (if, for example, applies to the path s in the vertical y direction s = A sin ( ω. T ) holds for the velocity v and the acceleration a ν = ṡ = A. ω. Cos ( ω. T ) and a = s̈ = - A. ω ^2. Sin ( ω.t ) Due to the high acceleration a with | a | = A.ω ² and the associated high frictional forces in the dead centers OT and UT, the strand shell or the casting powder, which is to ensure adequate lubrication of the strand in the mold, at these points particularly heavily loaded.

$$V=A_V\mathrm{.}\sin \left(2.\pi \mathrm{.}{f}_V\mathrm{.}t\right)=4.\sin \left(2.\pi \mathrm{.}\frac{100}{60}\mathrm{.}t\right)$$

The 2a, 2b show a non-inventive movement path of a two-dimensional oscillating Wide side plate (vertical oscillation and horizontal oscillation in the width direction of the broad side plate) of a mold. The Fig. 2a shows the time sequence of the oscillation (abscissa in seconds); the Fig. 2b shows the locus of the trajectory. For the trajectory in vertical V and horizontal H direction (in mm): $$H=A_H\mathrm{,}\sin \left(\mathrm{Second}\pi \mathrm{,}{f}_H\mathrm{,}t-O\right)=\mathrm{Second}\sin \left(\mathrm{Second}\pi \mathrm{,}\frac{200}{60}\mathrm{,}t-90°\right)$$

$$V=A_V\mathrm{,}\sin \left(\mathrm{Second}\pi \mathrm{,}{f}_V\mathrm{,}t\right)=\mathrm{4th}\sin \left(\mathrm{Second}\pi \mathrm{,}\frac{100}{60}\mathrm{,}t\right)$$

The locus in Fig. 2b has two pronounced dead centers OT, UT, so that the strand is heavily loaded at these points.

The Fig. 3a, 3b show the trajectory and the locus of a broad side of a mold for slab cross sections, which oscillates two-dimensionally (ie vertically and horizontally in the width direction of the broad side plate) according to the invention. The parameters of the oscillations are f _H = 33.3 / 60 Hz, f _V = 100/60 Hz, A _H = 2 mm, A _V = 4 mm and 0̸ = 90 °. From the locus shows that the trajectory has no dead points and is therefore favorable.

The FIGS. 4a, 4b show a further movement path according to the invention for a broadside plate of a mold. The parameters of the oscillations are f _H = 170/60 Hz, f _v = 100/60 Hz, A _H = 2 mm, A _V = 4 mm and Ø = 90 °. Also from this locus shows that the trajectory has no dead points and compared to the Fig. 3a, 3b is significantly longer (neither f _H / f _V nor f _V / f _H is an integer multiple). It is therefore extremely cheap.

From the Fig. 3 and 4 shows that the movement paths according to the invention of the broad side plates of the mold are much smoother than in the vertical, one-dimensional oscillation, in which the mold reverses the direction of movement in both the top and bottom dead center. Furthermore, the trajectories of the invention have no pronounced dead centers with direction reversal. The smoother motion path improves the lubricating effect of the casting powder and reduces the friction between the mold and the strand.

• The Making, Shaping and Treating of Steel (MSTS), Casting Volume, Kap. 15 (insbes. 15.6.8.1-15.6.8.4), AISE, 2003 .

In the Fig. 5 is a mold 1 of a continuous casting machine for slab formats shown schematically. For ease of illustration, the oscillation apparatus for the vertical oscillation of the mold (including the stationary support structure, the spring bands between the support structure and the mold frame 6 and the first oscillation drive for vertical oscillation of the mold 1) has not been shown. The concept of vertical mold oscillation has been known to the person skilled in the art since 1921 (Van Ranst); Hydraulic oscillation devices have been known since 1962 (Koopers). Furthermore, the devices for vertical oscillation of the mold are also known from the literature, for example

• The Making, Shaping and Treating of Steel (MSTS), Casting Volume, Chap. 15 (especially 15.6.8.1-15.6.8.4), AISE, 2003 ,

In Fig. 8 the second oscillation device 5 is shown in more detail. A rectangular, the two Breitseiten- 3, 3a, 3b and narrow side plates 2 of the mold 1 enclosing mold frame 6 is brought by the not-shown first oscillating means in a vertical oscillation V. The two narrow side plates 2 and the two wide side plates 3 form the rectangular mold cavity 4 (for the invention it does not matter if the mold cavity 4 is square or not; in particular, a wide side plate does not need to be longer than a narrow side plate). By a respective second oscillating device 5a, 5b is a broad side 3a, 3b relative to the oscillating in the vertical direction V mold frame 6 horizontally in the width direction H (ie in the width direction of the strand) of the wide side plate 3a, 3b oscillates. According to Fig. 7 The second oscillation drive 7, which is designed as a hydraulic cylinder 9, is supported on the mold frame 6 and acted upon as a second spring element elastic element 8 via the spring band, the wide side plate 3 together with the support plate 10 and the water tank 11 of the mold 1 in a horizontal oscillation H transversely to the thickness direction of the strand. The narrow side plates 2 adjoining the wide side plate 3 are not oscillated in the horizontal direction, but oscillate together with the mold frame 6 in the vertical direction V. In order to keep the friction between the wide and narrow side plates 3, 2 low, the plates each have sliding surfaces 12 Sintered metal on. The clamping unit 15 including the hydraulic clamping cylinder, not shown in detail, ensures that the mold cavity 4 is sealed in a fluid-tight manner, without, however, causing excessive friction between the plates.

Although at the Figures 5 and 8th Each broadside plate 3a, 3b is associated with its own second oscillation device 5 (and thus the two broadside plates can be moved in opposite directions), it would also be possible to accomplish the horizontal oscillation movement for both broadside plate 3a, 3b via a single second oscillation drive 5. In addition, depending on a second oscillating drive 5 could be arranged in the width direction on both sides of the wide side plate 3.

In order to avoid excessive friction between the water box 11, which is connected via the support plate 10 with the wide side plate 3a or 3b, and the fixed 13 and loose side 14 of the mold frame 6, the water box 11 is either not on the support structure 6 (eg may be provided between a gap between the water box 11 and the support structure 6), or sliding surfaces 12 are provided between the water box and the support structure.

In the Fig. 6 is the mold 1 shown obliquely from below, wherein the forming in the mold 1, not shown, strand is supported by a plurality of castors 16.

The Fig. 7 shows a representation of the mold 1 without the Losseiten 14 (see Fig. 6 ) of the mold frame 6. The loose side 14 of the mold 1 is clamped by the two clamping units 15 with the fixed side 13. Here, the clamping force is hydraulically adjustable.

While the invention has been further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

1

mold

2

Narrow side plate

3, 3a, 3b

Broadside plate

4

mold cavity

5, 5a, 5b

second oscillation device

6

mold frame

7

second oscillation drive

8th

second elastic element

9

hydraulic cylinders

10

support plate

11

cistern

12

sliding surface

13

fixed side

14

loose side

15

terminal unit

16

casters

f

frequency

H

horizontal width direction

OT

Top Dead Center

UT

Bottom dead center

V

vertical direction

Claims (18)

1. Method for oscillating a mould (1) of a continuous casting machine, the mould (1) comprising two narrow-side plates (2) and two broad-side plates (3, 3a, 3b), and the mould (1) oscillating with respect to a positionally fixed supporting structure in the vertical direction (V) with a first frequency f_V , characterized
   in that at least one broad-side plate (3, 3a, 3b) of the mould (1) oscillates horizontally in the direction of the width (H) of the broad-side plate (3, 3a, 3b) with a second frequency f_H, where f_V ≠ f_H, and
   in that, for all points of the locus of the broad-side plate (3), the magnitude of the velocity | v | is greater than 0.
2. Method according to Claim 1, characterized in that

   - the first frequency f_V is an integral multiple of the second frequency f_H, f_V = n. f_H with n ∈ {2, 3, 4, 5...}, or

   - the second frequency f_H is an integral multiple of the first frequency f_V, f_H = n. f_V with n ∈ {2, 3, 4, 5...} .
3. Method according to Claim 1, characterized in that

   - the first frequency f_V is not an integral multiple of the second frequency f_H, f_V ≠n. f_H with n ∈ {2, 3, 4, 5...}, or

   - the second frequency f_H is not an integral multiple of the first frequency f_V, f_H ≠ n. f_V with n ∈ {2, 3, 4, 5...} .
4. Method according to one of Claims 1 to 3, characterized in that the first frequency is greater than the second frequency, f_V > f_H.
5. Method according to one of Claims 1 to 4, characterized in that the amplitude of the vertical oscillation is greater than or equal to the amplitude of the horizontal oscillation.
6. Method according to one of Claims 1 to 5, characterized in that the two broad-side plates (3, 3a, 3b) of the mould (1) oscillate in opposite senses in the horizontal direction (H).
7. Method according to one of Claims 1 to 5, characterized in that the two broad-side plates (3, 3a, 3b) of the mould (1) oscillate in the same sense in the horizontal direction (H).
8. Method according to one of the preceding claims, characterized in that the broad-side plate (3, 3a, 3b) horizontally oscillates harmonically in the direction of the width (H) of the broad-side plate.
9. Apparatus for oscillating a mould (1) of a continuous casting machine, having

   - the mould (1) with a substantially rectangular mould cavity (5), the mould (1) comprising two narrow-side plates (2) and two broad-side plates (3, 3a, 3b);

   - a first oscillating device for the oscillation of the mould (1) with respect to a positionally fixed supporting structure in the vertical direction (V);

   characterized by

   - a second oscillating device (5) for the horizontal oscillation of at least one broad-side plate (3, 3a, 3b) of the mould (1) with respect to the adjacent narrow-side plates (2) in the direction of the width (H) of the broad-side plate (3, 3a, 3b), the broad-side plate (3, 3a, 3b) being designed displaceably with respect to the adjacent narrow-side plates (2) .
10. Apparatus according to Claim 9, characterized in that the apparatus comprises two second oscillating devices (5a, 5b), each second oscillating device being designed for the horizontal oscillation of a broad-side plate (3, 3a, 3b) of the mould (1) in the direction of the width (H).
11. Apparatus according to either of Claims 9 and 10, characterized in that the mould (1) comprises a mould frame (6) and the second oscillating device (5, 5a, 5b) comprises a second oscillating drive (7), the second oscillating drive (7) being connected to the mould frame (6) oscillating in the vertical direction (V) and to the broad-side plate (3).
12. Apparatus according to Claim 11, characterized in that the second oscillating device (5, 5a, 5b) comprises a second elastic element (8), which is arranged between the mould frame (6) and the broad-side plate (3, 3a, 3b), it being possible for the broad-side plate (3, 3a, 3b) to be made to undergo a horizontal oscillation in the direction of the width (H) of the broad-side plate (3, 3a, 3b) with respect to the mould frame (6) oscillating in the vertical direction (V) by the second oscillating drive (7).
13. Apparatus according to Claim 12, characterized in that the second elastic element (8) is a resilient band.
14. Apparatus according to one of Claims 11 to 13, characterized in that the second oscillating drive (7) is a linear motor.
15. Apparatus according to Claim 14, characterized in that the linear motor is a hydraulic linear motor, preferably a hydraulic cylinder (9), or an electric linear motor, preferably a piezoactuator.
16. Apparatus according to one of Claims 9 to 15, characterized in that a supporting plate (10) and a water tank (11) are arranged between the broad-side plate (3, 3a, 3b) and the mould frame (6).
17. Apparatus according to one of Claims 9 to 16, characterized in that the broad-side plate (3, 3a, 3b) and the adjacent narrow-side plates (2) have sliding surfaces (12), preferably of sintered metal, which allow a relative movement.
18. Apparatus according to one of Claims 9 to 17, characterized in that the first broad-side plate (3a) is connected to the fixed side (13) and the second broad-side plate (3b) is connected to the loose side (14) of the mould frame (6), the loose side (14) being connected to the fixed side (13) by way of a clamping unit (15), the clamping force of the clamping unit (15) preferably being hydraulically adjustable.

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