CA2178178A1

CA2178178A1 - Grinding machine

Info

Publication number: CA2178178A1
Application number: CA002178178A
Authority: CA
Inventors: Gunter Kneppe; Klaus-Dieter Haberkamm; Wolfgang Rohde
Original assignee: SMS Schloemann Siemag AG
Current assignee: SMS Siemag AG
Priority date: 1995-07-19
Filing date: 1996-06-04
Publication date: 1997-01-20
Also published as: DE19526280A1; JPH09103942A; EP0754504A1; KR970005528A; TW340810B; CN1145829A

Abstract

A grinding machine for grinding the surfaces of continuously cast slabs, including thin slabs and/or hot-rolled strip or strip to be hot-rolled, during the travel thereof in a rolling mill for the removal of objectionable surface portions, such as scale layers and/or texture defects or the like. A shaft extending across the material to be ground is provided, wherein a plurality of grinding rollers are attached axially one behind the other on the shaft so as to rotate with the shaft. Each grinding roller has a central hub member, wherein resilient lamellae or blades provided with an abrasive medium extend from the outer surface of the hub member.

Description

RAC~OUND OF THE lNv~ lON

1. Field of the Invention The present invention relates to a grinding machine for grinding the surfaces of continuously cast slabs, including thin slabs and/or hot-rolled strip or strip to be hot-rolled, during the travel thereof in a rolling mill for the removal of objectionable surface portions, such as scale layers and/or texture defects or the like, by means of rolls extending across the slab surfaces.

2. De-~cription of the Related Art A grinding machine of the above-describe type is disclosed, for example, in DE-OS 36 00 144. In that grinding machine, a grinding roll each is arranged at a right angle above and below the material to be ground, wherein the length of the grinding rolls exceeds the width of the material to be ground. The grinding rolls have a so-called CVC contour or continuous variable crown contour, so that it is possible to influence the surface configuration of the material being ground by actually displacing the grinding rolls.

21781~8 However, if surface defects are to be ground in addition to scale, it is necessary primarily to achieve the removal of material by means of the grinding machine; the possibility of influencing the surface configuration is of less significance in that case. In order to ensure the removal of material, the grinding roll is no longer sufficient. Since the grinding roll rests over a large surface area on the material to be ground, the grinding roll could achieve the necessary material removal only when the contact pressure of the grinding roll against the material to be ground is very high. In addition, without taking into consideration bending of the roll, the rigid grinding roll is capable primarily only of reaching the material areas to be ground which project out the most. If defects to be ground away are located in small indentations, these defects cannot be ground with the rigid roll.

In order to achieve substantial removals of material from hot material to be ground, for example, in the temperature range of 750C to 1200C, strip grinding machines have been proposed in the past which are capable of working on smaller and indented areas of the material to be ground, however, these grinding machines were not capable of applying sufficient grinding pressure on the material to be ground.

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-S~MMARY OF T~E lNV~N LlON

Therefore, it is the primary object of the present invention to further develop a grinding machine of the above-described type in such a way that all areas of the material to be ground can be processed and that a sufficiently high grinding pressure can be exerted on the material to be ground.

In accordance with the present invention, instead of each grinding roll described above, a shaft extending across the material to be ground is provided, wherein a plurality of grinding rollers are attached axially one behind the other on the shaft so as to rotate with the shaft. Each grinding roller has a central hub member, wherein resilient lamellae or blades provided with an abrasive medium extend from the outer surface of the hub member.

By dividing the grinding roll into several grinding rollers, the grinding element no longer rests over a large surface area and rigidly on the material to be ground. Together with high rates of rotation of the shaft supporting the hub members on which the lamellae are mounted, these lamellae ensure that the outer contour of the grinding rollers corresponds essentially to the usual roll cambers as a result of centrifugal forces, while the individual lamellae are capable in the contact area to adapt to the surfaces of the material to be ground, so that all areas of the material can be ground simultaneously and, consequently, material can be removed simultaneously at all locations; this is in contrast to the known rigid roll described above which initially grinds the area of the material to be ground which projects out to the greatest extent and, only after this area has been ground, the areas which do not project as much are ground.

The drive and the adjustment of the grinding rollers are effected through the common shaft, so that uniform grinding of the material over a large surface area thereof can be carried out with relatively simple means.

The lamellae of the grinding rollers may be brushes or, in accordance with another feature of the present invention, the grinding rollers may be so-called lamellae grinding rollers in which only the free end areas of the lamellae contribute to the grinding process.

In accordance with another feature, spacer elements are provided between adjacent lamellae. This makes it possible that the individual lamellae can be better cooled in the surrounding area.

However, in accordance with another feature, it is also possible to provide cooling medium nozzles for the lamellae.

In order to able to reduce the contact forces and to subject the lamellae to a smaller bending load, it is possible to provide spaces between the grinding rollers. However, in order to be able to work on the entire surface of the material to be ground, it is in that case necessary that the grinding rollers are periodically displaced in axial direction; it must be ensured in that case that the lamellae of the outermost grinding rollers are not moved completely over the edge area of the material to be ground, because the sides of the grinding rollers would otherwise be moved against the material to be ground when the grinding rollers are moved back, which could result in a destruction of the lamellae. Furthermore, it should be possible to adjust the axial displacement speed to the travel speed of the material to be ground, so that all areas of the material to be ground can in fact be worked on.

In order to make it possible to work on the entire surface area of the material to be ground without requiring an axial displacement of the rollers, even though there are distances between the grinding rollers, another feature of the present invention provides that a second shaft is arranged behind the first shaft in travel direction of the material to be ground, wherein, however, the grinding rollers of the second shaft are aligned so as to be located in axial direction in the spaces of the first shaft without grinding rollers.

The grinding rollers have a certain service life after which they must be replaced. In order to ensure a continuous operation of the grinding machine, it is suggested in accordance with another feature of the present invention to provide several shafts with grinding rollers one behind the other, so that the used grinding rollers can be replaced by means of appropriate changing units, while the grinding rollers on the remaining shafts can be moved toward the material to be ground and can be used for grinding the material.

In order to be able to better apply the high contact pressures onto the material to be ground and to reduce the bending stress on the shaft, it is possible to additionally support and adjust the shafts in the areas without grinding rollers.

In accordance with another proposal according to the present invention, the shafts supporting the grinding rollers are moved periodically in axial direction, so that a uniform grinding of the material is ensured even when the grinding rollers are located closely adjacent to each other. As a result, it is ensured that even between two grinding rollers which are arranged closely next to each other, there are no areas in which no grinding process takes place or in which grinding takes place insufficiently.

For discharging the material removed from the material being ground, suction nozzles are arranged at least above the material being ground. The material removed by the grinding rollers arranged below the material to be ground drops down as a result of gravity and can be collected with suitable means.

The shafts are subjected to high radiation heat, wherein the shafts arranged above the material to be ground must additionally withstand high convection heat. In addition, there is the heat produced by grinding which must be removed from the lamellae, so that, in accordance with a useful feature of the present invention, means are provided for conducting cooling agent onto or through the shafts.

In order to improve overlapping of the individual grinding areas, it is suggest in accordance with another feature of the present invention that the shaft extends at an angle deviating from 90C relative to the travel direction of the material to be ground.

The various features of novelty which characterize the invention are pointed out with particularity in the claims ~nn~ed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

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BRIEF DESCRIPTION OF THE DRAWING

In the drawing:

Fig. 1 is a schematic top view of a grinding machine according to the present invention, showing the various possibilities of configuring the grinding rollers; and Fig. 2 is a side view, on a larger scale, of a grinding roller.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Fig. 1 of the drawing shows a material 1 to be ground, wherein the material to be ground is a thin slab arriving from a continuous casting plant, not shown, and wherein the material 1 moves in the direction of an arrow 2 in a rolling mill, not shown. Grinding units 3 to 3'''' are arranged above and below the material 1. Of course, it is also possible to provide appropriate grinding units at the edges of the material 1.

The grinding units 3 to 3'''' have shafts 7 mounted through bearings 4, 4' and chocks 5, 5' in housings 6, 6' as illustrated, for example, only in connection with grinding unit 3. The shafts 7 can be driven for rotation by means of motors 8. The shafts 7 can be periodically displaced in axial direction by means of a displacement device 9. Of course, the shafts 7 can also be arranged so as to be stationary in axial direction, as illustrated, for example, in connection with grinding unit 3'.

The grinding unit 3 has a plurality of grinding rollers 10, 10', 10''... which are arranged closely next to each other and which cover the entire surface area of the material 1. This makes it possible to work on the entire surface of the material 1.
Accordingly, the grinding unit 10 essentially does not require a displacement drive 9. The displacement drive 9 shown in connection with grinding unit 3 merely serves to improve the uniformity of grlndlng .

For a continuous operation of the grinding machine, it is sufficient if only two grinding units 3 are provided one behind the other in travel direction of the material 1, so that always one grinding unit 3 can be in the position of operation, while the second grinding unit 3, not shown, can be exchanged and replaced by changing devices, not shown.

The grinding unit 3' has grinding rollers 10, 10~, 10''....
wherein spaces are provided between the grinding rollers. Cooling air for the grinding rollers can be blown into the spaces between the rollers. For this purpose, a pump 11 is provided which is connected through lines 12 to the nozzles 13. Moreover, the grinding unit 3' includes, for example, a suction nozzle 20 which is connected to a pump 21 and is capable of withdrawing the material particles produced by grinding. Of course, the other grinding unit can also be provided with these cooling devices and/or material removing devices.

In the grinding unit 3'', there are also distances between the individual grinding rollers 10, 10', 10''..., wherein the grinding rollers 10 of the grinding unit 3'' are aligned so as to be located in the free spaces between the grinding rollers 10 of the grinding unit 3'. Furthermore, the grinding unit 3'' includes a cooling medium pump 14 for conducting cooling medium through appropriate lines to the respective shafts 7. This cooling unit can also be arranged at all other grinding units.

It is possible to arrange the grinding unit 3' and the grinding unit 3'' one behind the other without axial displacement drives. In that case, for a continuous operation, it is then necessary to provide, for example, another equal pair of grinding units. Of course, one of the other grinding units 3, 3''', 3'''' can be combined with the units 3', 3''.

However, another possibility is to provide the grinding unit 3~ with an axial displacement drive 9. By periodically displacing the shaft in axial direction, a continuous operation is possible already by using at least two of these grinding units 3''.

The grinding unit 3''' demonstrates that the material 1 can be sufficiently ground by providing only a few grinding rollers and by axially displacing the shaft 7. In order to be able to apply a sufficiently large contact force against the material 1 in this grinding unit, the shaft 7 has additional adjustable bearings 15.

It is even conceivable to provide a grinding unit with only one grinding roller on the shaft 7. However, in that case, it would be useful to mount the shaft so as to be stationary in axial direction and to arrange the grinding roller so as to be axially displaceable, while being connected to the shaft so as to rotate therewith; in addition, an appropriate displacement drive for moving the grinding roller in axial direction would have to be provided.

The grinding unit 3'''' has a shaft 7 which is arranged so as to be inclined at an angle relative to the remaining shafts 7. Of course, grinding roller arrangements as they are shown in connection with grinding unit 3 through 3''' can be arranged on this inclined shaft 7. Cooling units 11 through 15 can also be provided in this grinding unit 3''''. For a continuous operation, several grinding units 3'''' can be arranged one behind the other, wherein the angle of all shafts relative to the travel direction of the material 1 may be identical or the angle may also be different or directed in opposite direction.

Fig. 2 shows a grinding roller 10 composed of a hub member 16 and lamellae 18 attached to the outer surface 17 of the hub member 16. Spacer members 19 are provided between the lamellae 18, wherein the spacer members 19 increase the distance between the lamellae 18, so that a better cooling of the individual lamellae 18 is possible.

While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

Claims

1. A grinding machine for grinding surfaces of continuously cast slabs, including thin slabs and/or hot-rolled strip or strip to be hot-rolled, during movement thereof in a rolling mill for removing objectionable surface portions, such as scale layers and/or texture defects or the like, the grinding machine comprising at least one shaft extending across the material to be ground, a plurality of grinding rollers being mounted on the at least one shaft one behind the other in axial direction of the shaft, the grinding rollers being mounted on the at least one shaft so as to rotate therewith, each grinding roller having a central hub member, the hub member having an outer surface, a plurality of resilient lamellae provided with an abrasive medium being attached to the outer surface of the hub member.

2. The grinding machine according to claim 1, wherein each hub member has a width, and wherein the lamellae extend across the width of the hub member.

3. The grinding machine according to claim 2, further comprising spacer elements between adjacent lamellae.

4. The grinding machine according to claim 1, wherein the grinding rollers mounted on the least one shaft are spaced apart from one another, further comprising means for periodically moving the grinding rollers in axial direction of the shaft.

5. The grinding machine according to claim 1, comprising at least two shafts, wherein the grinding rollers mounted on each shaft are spaced apart from one another, wherein the grinding rollers of one of the two shafts are arranged offset in axial direction of the shafts relative to the grinding rollers of another of the two shafts.

6. The grinding machine according to claim 1, comprising a plurality of shafts with grinding rollers for ensuring a continuous grinding operation.

7. The grinding machine according to claim 1, comprising bearings in shaft areas between grinding rollers.

8. The grinding machine according to claim 1, comprising means for periodically moving the at least one shaft in axial direction.

9. The grinding machine according to claim 1, further comprising suction nozzles mounted adjacent the grinding rollers.

10. The grinding machine according to claim 1, further comprising cooling medium nozzles directed toward the lamellae of the grinding rollers.

11. The grinding machine according to claim 1, comprising means for conducting cooling medium against or through the at least one shaft.

12. The grinding machine according to claim 11, wherein the means for conducting cooling medium comprises a cooling medium pump.

13. The grinding machine according to claim 1, comprising at least two shafts, wherein the shafts extend at an angle deviating from 90 degrees relative to the travel direction of the material being ground.

14. The grinding machine according to claim 1, wherein the grinding machine is mounted immediately downstream of a continuous casting machine for operating in a temperature range of between 750°C and 1200°C.