GRINDING DEVICE

Abstract

A device for grinding a continuously cast product, in particular a slab (11), a billet or a block. The Device has at least one rotationally operated abrasive disk (10), which is attached to a grinding head (15). At least one high-pressure air nozzle (14) is arranged on the grinding head (15). The high-pressure air nozzle blows the continuously cast product free of particles adhering to or lying on the continuously cast product prior to grinding.

Description

TECHNICAL FIELD

The present invention pertains to a device for grinding a continuously cast product, in particular a slab, a billet or a block, with at least one grinding wheel, which is operated in a rotating manner and is fastened to a grinding head.

TECHNICAL BACKGROUND

Semifinished products made of steel, in particular in the form of steel slabs, which are manufactured in a slab continuous-casting plant, can be processed with such grinding devices. Such slabs are, as a result, cuboid. The slab coming from the casting operation has production-related surface defects, which are, for example, in the form of grooves, furrows, cracks or other undesired inclusions.

Various processes, such as scarfing, milling or grinding are proposed for surface processing.

Scarfing has the drawback that melted-off material cannot again be melted down without treatment because of the high oxygen content. A surface treatment by means of milling is therefore proposed in EP 2 032 285. As a drawback in this case, hot milling chips develop, which have to be conveyed away from the work area. In addition, the plain-milling cutters or face-milling cutters used have to be cooled in order to prevent overheating of the milling cutters, which would lead to a considerable wear. Cooling lubricants are used for cooling, which make an immediate further processing of the removed chips impossible. Before such chips are melted down again, they have to be washed and be separated from the cooling lubricants; the cooling lubricant has to be disposed of separately as hazardous waste.

It has been mentioned in this connection that conveying away of the chips can be supported by aids such as an air blower or a water jet, which are arranged behind the milling station. There is the risk during the grinding that dust or other undesired particles that adhere to the surface are pressed into the ground surface during the grinding, which minimizes the quality of the ground surface. Exhaust units or admissions of cooling water help only to a limited extent.

SUMMARY

The present invention pertains to both surface grinding operations, in which the grinding wheel is moved back and forth in an oscillating manner vertically to the direction of feed of a slab, and such grinding devices, in which a grinding arm with a grinding tool fastened at the end is oriented with its longitudinal axis and with an acute angle on the order of between 25° to about 65° to the rotation axis of the grinding wheel. Such devices are described, for example, in DE 101 48 183 A1. The object of the present invention is to provide a grinding device, which performs a grinding operation leading to an improved surface quality.

This object is accomplished by a device which is characterized in that at least one high-pressure air nozzle that clears particles adhering to or lying on the surface of the continuously cast product before the grinding operation is arranged on the grinding head. The advantage of such a grinding device is that dust particles, metal splinters or other adhering particles are removed before the grinding stone reaches the processing zone in question. In particular, ground-down particles, which are harder than (slab) steel, are blown away from the grinding wheel, as a result of which these particles are not pushed into or pressed into the slab surface during the grinding. The high-pressure air nozzle or nozzles is/are integrated with the grinding head, so that due to this mounting, the distance of the grinding wheels to the high-pressure air nozzle and the direction of spraying thereof can be set in a fixed manner and remains unchanged even in case of a movement of the head for guiding the grinding wheel. Special disposal problems such as in case of the use of cooling lubricants or other liquids or structurally complicated devices for collecting liquid coolant are not necessary. The surface quality of the material to be ground being treated can be improved considerably due to the clearing of the semifinished product surface before the grinding. In contrast to milling operations in which chips accumulate which then have to be disposed of, the blown-away grinding dust can be disposed of in a considerably easier manner, for example, by suction.

According to another embodiment of the present invention, two or more high-pressure air nozzles are arranged on the grinding head on both sides of the grinding wheel or of each grinding wheel, so that at least one high-pressure air nozzle, which blows away particles before the grinding operation, can be operated in case of a change in grinding direction. In this manner, a grinding operation which moves back and forth in an oscillating manner is also possible without retrofitting the grinding head. The application of pressure during the grinding can take place by means of the same control that also introduces the change in direction during the grinding. Existing high-pressure air nozzles can be fed alternately from one and the same compressed air source.

Not only the particles lying on or adhering to the surface in front of the grinding wheel, but also the grinding dust developing during the grinding, can preferably be immediately blown away by using a flat blast nozzle.

The pressures used are preferably at least 2 bar (2×10⁵ Pa), in particular between 5 bar and 120 bar (5×10⁵ Pa to 12×10⁶ Pa). According to another embodiment of the present invention, the air outlet velocity at the nozzle is at least 100 m/sec, preferably more than 200 m/sec.

An exemplary embodiment of the present invention is shown in the drawings. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic diagram for showing the grinding treatment of a slab known according to the state of the art;

FIG. 2 is a schematic diagram according to the present invention with an additionally used high-pressure air nozzle;

FIG. 3 is a schematic view of a first embodiment of a grinding head with a grinding wheel as well as with a single nozzle; and

FIG. 4 is a schematic view of a second embodiment of a grinding head with a grinding wheel and with two mounted high-pressure air nozzles.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to the drawings, along the arrow 12 in the example shown until the grinding operation has been performed over the entire length of the slab. The slab 11 is then moved forward in the vertical direction towards the longitudinal axis in order to pass through the next grinding path in the direction of the longitudinal axis.

Remaining grinding particles or metal particles or dust particles as well as defect inclusions on the slab surface are shown by reference number 13.

According to the present invention and as can be seen in FIG. 2, the slab is moved in the direction of the arrow 12 during the grinding operation. The stationary grinding wheel 10 is located on a grinding head, not shown, which is additionally used as a holder for a nozzle 14, which is flattened toward the front side and forms a nozzle slot, from which air flows under high pressure. The air stream is directed such that it blows away particles and dust lying in front of the grinding wheel as well as grinding dust that is generated by the grinding operation during the abrasion of the grinding wheel.

As can be seen in FIG. 3, the grinding wheel 10 as well as the high-pressure air nozzle 14 are fastened to a grinding head 15.

The relative direction of forward motion of the grinding head in relation to the slab 11 is identified by the arrow 16.

The embodiment according to FIG. 4 differs from the embodiment described above in that two high-pressure air nozzles 141 and 142 are provided, which are arranged on both sides offset to the grinding wheel 10 and which are operated alternatingly, so that the movements of the grinding wheel in relation to the slab take place in two directions (see double arrow 17). Compressed air is applied to each high-pressure air nozzle, which in a slightly offset manner clears unprocessed grinding areas as well as developing grinding dust. The exiting air flow is identified by reference number 18.

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

Claims

1. A device for grinding a continuously cast product, the device comprising: a grinding head;at least one grinding wheel configured to be rotatingly operated the at least one grinding wheel being fastened to the grinding head; andat least one high-pressure air nozzle, which clears particles adhering to or lying on the surface of the continuously cast product before a grinding operation, the at least one high-pressure air nozzle being arranged on the grinding head.

2. A device in accordance with claim 1, further comprising another high-pressure air nozzle to provide at least two high-pressure air nozzles with the high-pressure air nozzles arranged on the grinding head on both sides of the grinding wheel or in the grinding wheel, so that at least one of the high-pressure air nozzles, which blows away particles before the grinding operation, can be operated in case of a change in grinding direction.

3. A device in accordance with claim 1, wherein the nozzle is arranged in relation to the grinding wheel such that the nozzle both blows away particles before the grinding operation and is used for the immediate blowing away of developing grinding dust.

4. A device in accordance with claim 1, wherein the high-pressure air nozzle generates an air pressure of at least 2×105 Pa.

5. A device in accordance with claim 1, wherein the high-pressure air nozzle is configured as a flat blast nozzle and/or is configured for discharging air with an air outlet velocity of at least 100 m/sec.

6. A device in accordance with claim 2, wherein the nozzle is arranged in relation to the grinding wheel such that the nozzle both blows away particles before the grinding operation and blows away grinding dust developing during the grinding operation.

7. A device in accordance with claim 2, wherein the high-pressure air nozzle generates an air pressure of at least 2×105 Pa.

8. A device in accordance with claim 3, wherein the high-pressure air nozzle generates an air pressure of at least 2×105 Pa.

9. A device in accordance with claim 1, wherein the high-pressure air nozzle generates an air pressure of from 5×105 Pa to 12×106 Pa.

10. A device in accordance with claim 2, wherein the high-pressure air nozzle generates an air pressure of from 5×105 Pa to 12×106 Pa.

11. A device in accordance with claim 3, wherein the high-pressure air nozzle generates an air pressure of from 5×105 Pa to 12×106 Pa.

12. A device in accordance with claim 2, wherein the high-pressure air nozzle is configured as a flat blast nozzle and/or is configured for discharging air with an air outlet velocity of at least 100 m/sec.

13. A device in accordance with claim 3, wherein the high-pressure air nozzle is configured as a flat blast nozzle and/or is configured for discharging air with an air outlet velocity of at least 100 m/sec.

14. A device in accordance with claim 4, wherein the high-pressure air nozzle is configured as a flat blast nozzle and/or is configured for discharging air with an air outlet velocity of at least 100 m/sec.

15. A device in accordance with claim 1, wherein the high-pressure air nozzle is configured as a flat blast nozzle and/or is configured for discharging air with an air outlet velocity of at least 200 m/sec.

16. A device in accordance with claim 2, wherein the high-pressure air nozzle is configured as a flat blast nozzle and/or is configured for discharging air with an air outlet velocity of at least 200 m/sec.

17. A device in accordance with claim 3, wherein the high-pressure air nozzle is configured as a flat blast nozzle and/or is configured for discharging air with an air outlet velocity of at least 200 m/sec.

18. A device in accordance with claim 4, wherein the high-pressure air nozzle is configured as a flat blast nozzle and/or is configured for discharging air with an air outlet velocity of at least 200 m/sec.