EP1391256A1 - Fluid cooled mould for continuous casting of metals - Google Patents

Abstract

Liquid-cooled mold comprises mold plates (1) made from copper or copper alloy held on support plates (2) using a bolt (6) having a bolt head (12) and a hinge arrangement (13). The hinge arrangement has a first hinged part and a second hinged part assigned to the rear side of the support plate with sliding surfaces facing each other. A sliding element is arranged between the sliding surfaces of the hinged parts.

Description

The invention relates to a liquid-cooled mold for the continuous casting of Metals with the features of the preamble of claim 1.

From DE 195 81 604 T1 a continuous casting mold for metals is known, in which a uniformly thick mold plate made of copper or copper material with a Steel support plate is connected by a variety of bolts. As a result of thermal expansion of the mold plates in the casting operation occurs especially with short bolts to a not negligible bending and Tensile stress on the bolts. Depending on the type of attachment of the bolts to the In the case of welded-on bolts, the mold plate can fail Welded connections are made or with bolts screwed in Overstressing of the thread. In extreme cases, even cracks in the Mold plate occur. To avoid this, DE 195 81 604 T1 provided the mold plate with the support plate in a sliding arrangement with each other to bolt, so that the mold plate is three-dimensional relative to the support plate is movable. This is done by using sliding fasteners achieved and by oversizing the through holes in the Support plate. A lateral or two-dimensional movement of the bolts and consequently the mold plate is possible. In addition to this measure disc-shaped spring washers proposed, preferably in a stacked arrangement, to maintain the pretension of the bolt even at high temperatures receive. The spring washers serve as one from a transmission point of view Joint arrangement with one degree of freedom, namely as a sliding seat.

This approach has the disadvantage that when using steel Spring washers a not inconsiderable static friction between the spring elements occurs. Because of the variety of contact areas between the spring washers as well the static friction forces add up between the support plate and the mold plate, so that a tension-free relative displacement of the mold plate is excluded.

Proceeding from this, the object of the invention is a liquid-cooled To improve the mold for the continuous casting of metals, that the static friction between the support plate and the mold plate is reduced and a uniform expansion of the mold plate with respect to the support plate is possible is.

The invention solves this problem by the features of claim 1.

It is essential to the invention that a joint arrangement between the bolt head and the back of the support plate is provided with articulated members, each one are assigned to the components mentioned, the articulated members being mutually exclusive have facing sliding surfaces, between which a sliding element cannot be lost is incorporated.

Joint arrangements in the sense of the invention are bearings that have a lateral Movement of the bolt in a larger than the bolt diameter Allow through hole of the support plate and thus an essentially Allow parallel relative movement between the mold plate and the support plate. A sliding element in the sense of the invention is any element that is suitable for Reduce static friction and / or sliding friction between the sliding surfaces.

A sliding surface or a joint member is fixed at least indirectly Support plate assigned while the corresponding sliding surface or the corresponding Articulated member preferably laterally to the longitudinal axis of the bolt relative movement takes place. The sliding element is particularly ring-shaped configured and penetrated by the bolt and thereby captive between the Articulated members held. The sliding element can be used as a separate component between the Joint members may be included.

According to the features of claim 2, it is possible to use the sliding element Execute sliding coating, the at least one of the sliding surfaces insoluble assigned. That is, only one of the sliding surfaces or both sliding surfaces can be provided with a sliding coating. The sliding coating is suitable to determine the static friction value and / or the sliding friction value between the To reduce joint members and thus a relative movement of the bolt to simplify compared to the support plate.

Sliding coatings, the polytetrafluoroethylene, are considered to be particularly useful (PTFE) included. By using PTFE, the Adhesion and sliding friction values compared to comparable metallic sliding surfaces be greatly reduced.

It is considered advantageous if the static friction value between the Sliding surfaces is less than 0.1. Especially when using PTFE containing In the context of the invention, sliding coatings are also possible To achieve static friction values between the sliding surfaces less than 0.04. The The stiction values given relate to the dry friction between the sliding surfaces. It is of course also within the scope of the invention possible to provide additional lubricants between the sliding surfaces to this way to reduce friction. In particular, too Solid lubricants are used. These include e.g. Connections with To understand layered lattice structure, such as graphite, molybdenum sulfide, dichalcogenides, Metal halides, graphite fluoride, hexagonal boron nitride. To the solid lubricants also include oxidic and fluoride compounds of transition and Alkaline earth metals, also soft metals such as lead and polymers, especially fluorine containing plastics such as PTFE.

In addition to detachable or non-detachable sliding elements assigned to the articular surfaces in Form of solid lubricants in which the sliding surfaces are parallel to each other are aligned, it is also possible with non-parallel sliding surfaces provide mechanical sliding elements, with the help of a relative movement is made possible. For this purpose, according to the features of claim 6, that the sliding surfaces of the joint members are concave and each with a Pendulum disc with a spherical hood-shaped surface in engagement. The Pendulum disc serves as a sliding element between the sliding surfaces. The Pendulum disc is configured in a ring shape and has the sliding surfaces facing spherical hood-shaped surfaces. In the event of a relative displacement of the articular members there is an angular displacement of the pendulum disc, which is within the concave Sliding surfaces is freely movable.

The sliding surfaces are configured according to claim 7 as a conical socket. During one Ball socket a better power transmission and guidance of the pendulum disc is only possible with a conical socket only a linear guide given between the pendulum disc and the link. A line touch has the advantage of smaller contact areas and also with a suitable material pairing lower frictional forces.

Two-part pendulum disks can be used particularly cheaply because these are available as standard parts. Such pendulum discs are also called Ball disks and have a spherical cap-shaped surface and an annular flat radial surface. Two of these spherical washers can be used as Serve half of a pendulum disc, the disc halves with their Radial surfaces facing each other and facing outwards spherical hood-shaped surfaces are inserted between the joint members (Claim 8). Of course, it is also possible within the scope of the invention that Pendulum disks in one piece, each with an outward-facing spherical cap Surface.

One is essential for a secure connection of the mold plates to the support plates sufficient tension of the bolts. The necessary preload must be used can be maintained even with strong thermal fluctuations. additionally it must be taken into account that when using a pendulum disc it is not only lateral There are displacements in relation to the longitudinal axis of the bolt, but depending on the position the pendulum disc also slight changes in the direction of the longitudinal axis. That is, the distance between the joint members varies depending on the location of the Bob. It is therefore for the fatigue strength of the bolt connection Suitable for sliding coatings and necessary for pendulum disks, between the Bolt head and the back of the support plate at least one spring element integrate (claim 9). Both spring washers can be used as spring elements also elastomers, such as rubber, serve between the Bolt head and the first joint member and between the second joint member and the support plate can be provided. Of course it is also possible to provide multiple spring elements in a stacked arrangement to provide high thermal to compensate for changes in length and the pretensioning force of the Maintain bolt connection.

In addition to the sliding surfaces in the area of the bolt arrangement, however, there are also one Numerous other contact surfaces on the rear side of the mold plate and the its side of the support plate facing. Depending on the Bolt applied normal forces is in the joint between the mold plate and the support plate with considerable frictional forces, which according to the characteristics of claim 10 is counteracted in that between the parallel mutually movable contact surfaces of the mold plate and the support plate Lubricant is incorporated. Although the material pairing steel - copper already has a reduced sliding friction value, this can be achieved by additional Measures are further reduced. The preferred lubricants here Solid lubricants are used, which are insoluble with the respective contact surfaces of the Mold plate and / or the support plate are connected. The lubricants are preferably coatings (claim 11). This can be polymeric Be coatings, in particular based on PTFE (claim 12) or flat sliding elements (claim 13), such as sliding disks or sliding rings with which the static friction value between the contact surfaces preferably from a value can be reduced to less than 0.1 (claim 14).

Of course, only those areas of the mold are within the scope of the invention equipped with friction-reducing lubricants or sliding elements in which a relative movement is also desired. For a defined extension of the Mold plate, it can be useful, for example, the central area of the Mold plate firmly bolted to the support plate so that from this area assuming a uniform thermal, stress-free expansion of the Mold plate is possible.

Figur 1

im Schnitt einen Teilbereich einer mit einer Stützplatte durch einen Bolzen verbundenen Kokillenplatte;

Figur 2

in vergrößerter perspektivischer Darstellung den Bolzen der Figur 1 einschließlich einer Gelenkanordnung und

Figur 3

einen Bolzen mit einer weiteren Ausführungsform der Gelenkanordnung in perspektivischer Darstellung.

The invention is explained in more detail below on the basis of the exemplary embodiments illustrated in the drawings. Show it:

Figure 1

in section a portion of a mold plate connected to a support plate by a bolt;

Figure 2

in an enlarged perspective view the bolt of Figure 1 including a hinge arrangement and

Figure 3

a bolt with a further embodiment of the joint arrangement in a perspective view.

Figure 1 shows in cross section the connection area of a mold plate 1 made of copper or a copper alloy which is attached to a backing plate 2 at the rear. The Support plate 2 can be both an adapter plate and a component of one water box not shown.

In this exemplary embodiment, there is between the mold plate 1 and the support plate 2 a cooling gap 3 through which coolant flows. This extends between spaced-apart plateau bases 4, which result from the Elevate the coolant side 5 of the mold plate 1 in an island-like manner. In the illustrated Platform base 4 has a bolt 6 screwed in the center. The bolt 6 fits into one Threaded insert 7 in the platform base 4. The bolt 6 passes through with play Through hole 8 in the support plate 2. The through hole 8 is in the direction to the back 9 of the support plate 2 in diameter to a cylindrical Counterbore 10 expanded. On the one that extends in the radial direction The bottom of the bore 11 of the counterbore 10 engages over the one in the counterbore 10 arranged bolt head 12 applied clamping force incorporating a Joint arrangement 13 on the support plate 2. The joint arrangement is a Sliding seat, the thermally induced displacement of the mold plate 1 across Longitudinal axis LA of the bolt 6 enables. A relative shift is fundamentally only possible in that the diameter of the through hole 8 and Bolts 6 are dimensioned differently. The joint arrangement also serves to this, the static friction between the serving as a fixed camp Support plate 2 and mold plate 1 acting as a floating bearing. Accordingly, the joint arrangement 13 has a first bolt head 12 assigned upper link 14 and one of the rear 9 and the Bore bottom 11 in the rear 9 assigned second lower joint member 15, that acts as a fixed bearing (Figure 2). The joint members 14, 15 are each as Shaped washers and are penetrated centrally by the bolt 6. Here is the diameter D of the upper joint member 14 acting as a floating bearing is smaller dimensioned as the outer diameter D1 of the lower joint member 15 a lateral displacement of the upper joint member 15 without lateral hindrance possible. The lower link 15 is in its diameter D1 on the Diameter D2 of the counterbore 10 matched, so that with the exception of usual tolerances, the joint member 15 does not laterally within the counterbore 10 is relocatable. The joint member 15 thereby fulfills its function as a fixed bearing.

To reduce static friction and sliding friction, they face each other Sliding surfaces 16, 17 of the articulated members 14, 15 matched to one another in such a way that the static friction value is less than 0.1. This is shown in FIG Embodiment, the upper link 14 on its sliding surface 16 with a PTFE coating, which thus acts as a sliding element 18 from the bolt 6 is held captive between the sliding surfaces 16, 17. The sliding surface 17 of the lower link is on the PTFE coating in the way matched that their surface has a low roughness. As a link 15 can hence a metallic washer with a polished, hardened or ground Surface are used.

Above the joint member 14 is a support plate 19 of the same diameter arranged, which are configured in one piece on the bolt head 12 Radial collar 20 is arranged smaller diameter. The support disc 19 can optionally inserted below the bolt head 12 to the clamping forces of the Screw connection optimally towards the joint arrangement 13 underneath transfer. The support disk 19 can also be made in one piece with the bolt head 12 be trained. The bolt head 12 itself can be made in one piece with the bolt 6 be trained, that is, be a screw head, or also as a nut a threaded stud bolt. The bolt 6 itself can be integrally or positively connected to the mold plate 1.

In the direction of the bottom 11 of the counterbore 10 closes below of the lower link 15 a spring element 21. This can be, for example Ring disk made of elastomeric material, e.g. Rubber, be. It can too several spring elements 21 can be provided in a stacked arrangement.

As an additional measure to reduce the friction between the mold plate 1 and the support plate 2 is provided, the contact surfaces 22, 23 between to provide the mold plate 1 with a lubricant. The contact surfaces 22, 23 are in this embodiment in the area of the plateau base 4. Here For example, a flat solid lubricant can be incorporated. Thereby the support plate is opposite the mold plate in the connection area only in contact via sliding elements and lubricants, so that an effective Reduction of the prevailing static friction value is given.

FIG. 3 shows another embodiment of a joint arrangement a bolt 6 'designed as a screw 23 passes through one in the middle Joint arrangement 24. In its structure from the bottom up is below the Bolt head 12 'first arranged a first annular spring element 21' which is followed by a second annular spring element 21 ". This is followed by the upper one Joint member 25 a preferably hardened steel disc with in the image plane integrated cone at the bottom. The joint member 25 acts in a way as a conical pan. In reverse configuration is the bottom one Joint member 26 with one pointing in the direction of the bolt head 12 ' conical receptacle. That is, that in the illustration in FIG. 3 are not visible sliding surfaces of the articulated members 25, 26 configured in the shape of a truncated cone. Between the joint members 25, 26 is one Pendulum disc 27 arranged in the direction of the link members 25, 26th facing surfaces 28, 29 are designed spherical hood-shaped and with the Conical pans of the articulated members 25, 26 are in line contact.

In this embodiment, the pendulum disc 27 consists of an upper one Half of the disc 29 and a lower half of the disc 30. The disc halves 29, 30 are configured identically and vice versa with their flat radial surfaces placed on top of each other. The fact that the pendulum disc 27 in the conical pans Joint members 25, 26 is freely movable, a relative movement of the upper joint member 25 and thus the bolt 6 'compared to that as a fixed bearing acting lower joint member 26 take place. The relative movement is here not only to compensate for possible angular deviations between the joint members 25, 26, but in particular also in a lateral displacement transverse to Longitudinal axis of the bolt 6 '. With a purely lateral shift is due to the given geometry, however, a height compensation within the Joint arrangement 24 required. The height shift of the upper joint 25 compared to the lower link 26, however, is only a fraction of the lateral shift. It has been shown that with a lateral displacement of about 3 mm the height shift is about 0.1 mm. The height shift can via the spring elements 21 ', 21 "while maintaining the bias be compensated.

REFERENCE NUMBERS

1 -

mold plate

2 -

support plate

3 -

Cooling gap between 1 u. 2

4 -

Plateau base v. 1

5 -

Coolant side v. 1

6 -

bolt

6 '-

bolt

7 -

Thread insert in 4

8th -

Through hole in 2nd

9 -

Back v. 2

10 -

Counterbore in 9

11 -

Bohrgrund von v. 10

12 -

Bolt head v. 6

12 '-

Bolt head v. 6 '

13 -

joint arrangement

14 -

Joint member v. 13

15 -

Joint member v. 13

16 -

Sliding surface v. 14

17 -

Sliding surface v. 15

18 -

Sliding element on 16

19 -

Support disc under 20

20 -

Radial collar on 12

21 -

spring element

21 '-

spring element

21 "-

spring element

22 -

Contact area v. 2

23 -

Contact area v. 1

24 -

joint arrangement

25 -

Joint member v. 24

26 -

Joint member v. 24

27 -

Pendulum disc v. 24

28 -

Surface v. 27

29 -

upper disc v. 27

30 -

lower half of disc 27

D -

Diameter of 14

D1 -

Diameter of 15

D2 -

Diameter of 10

LA -

Longitudinal axis v. 6

Claims (14)

Liquid-cooled mold for the continuous casting of metals, comprising mold plates (1) made of copper or a copper alloy, which are held at the rear on support plates (2) by means of a multiplicity of bolts (6, 6 '), the bolts (6, 6') in the region of the rear sides (9) of the support plates (2) facing away from the mold plates (1) have bolt heads (12, 12 ') and between the bolt heads (12, 12') and the rear sides (9, 11) relative movements between the mold plates (1) and joint arrangements (13, 24) enabling the support plates (2) are incorporated, characterized in that the joint arrangements (13, 24) each have a first joint member (14, 25) associated with the bolt head (12, 12 ') and a second one on the rear side (9, 11) of the support plate (2) associated joint member (25, 26) with mutually facing sliding surfaces (16, 17), wherein a sliding element between the sliding surfaces (16, 17) of the joint members (14, 15; 25, 26) (18; 27) captive is incorporated. Liquid-cooled mold according to claim 1, characterized in that the sliding element (18) is a non-detachable sliding coating connected to at least one of the sliding surfaces (16). Liquid-cooled mold according to claim 2, characterized in that a component of the sliding coating is polytetrafluoroethylene (PTFE). Liquid-cooled mold according to claim 2 or 3, characterized in that the static friction value (µ ₀ ) between the sliding surfaces is less than or equal to 0.1. Liquid-cooled mold according to claim 4, characterized in that the static friction value (µ ₀ ) between the sliding surfaces is less than or equal to 0.04. Liquid-cooled mold according to Claims 1 to 5, characterized in that the sliding surfaces of the articulated members (25, 26) are designed to be concave and are each in engagement with a pendulum disc (27) with a spherical cover-shaped surface (28). Liquid-cooled mold according to claim 6, characterized in that the concave sliding surfaces are configured as a conical socket. Liquid-cooled mold according to claim 6 or 7, characterized in that the pendulum disc (27) is divided into an upper disc half (29) and a lower disc half (30), each with a one-sided spherical cap-shaped surface (28). Liquid-cooled mold according to one of claims 6 to 8, characterized in that at least one spring element (21, 21 ', 21 ") is incorporated between the bolt head (12, 12') and the rear (9, 11) of the support plate (2) , Liquid-cooled mold according to one of claims 1 to 9, characterized in that a lubricant is incorporated between the contact surfaces (22, 23) of the mold plate (1) and the support plate (2) which are movable parallel to one another. Liquid-cooled mold according to claim 10, characterized in that the lubricant is a non-detachable coating connected to the respective contact surfaces (22, 23) of the mold plate (1) and / or the support plate (2). Liquid-cooled mold according to claim 11, characterized in that a component of the sliding coating is polytetrafluoroethylene (PTFE). Liquid-cooled mold according to one of Claims 10 to 12, characterized in that flat sliding elements are arranged between the contact surfaces (22, 23) of the mold plate (1) and the support plate (2) which are movable parallel to one another. Liquid-cooled mold according to one of claims 10 to 13, characterized in that the static friction value (µ ₀ ) between the contact surfaces (22, 23) is less than or equal to 0.1.

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