LU85389A1 - DEVICE FOR DECALAMINATING METAL STRIPS - Google Patents

Description

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* C 2229/8306.

METALLURGICAL RESEARCH CENTER -CENTRUM V00R RESEARCH IN DE METALLURGIE,

Non-profit association -Vereniging zonder winstoogmerk in BRUXELLES, (Belgium).

Device for descaling metal strips.

The present invention relates to a device for mechanical descaling of metal strips, in particular steel strips. It relates more particularly to a descaling device which can be integrated into a line for processing hot-rolled strips, comprising a pickling installation, a tandem rolling mill, a degreasing installation, an annealing oven, a skin-pass rolling mill and an inspection post.

It is known that the various installations constituting such a line operate at rates varying greatly from one installation to another. This is the case, for example, between the tandem rolling mill, from where the strip exits at a speed of 1100 m / min. at ^ 1500 m / min., and the annealing station which only allows speeds of the order of 200 m / min. at 250 m / min. This results in a

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t f - 2 - marked incompatibility between the various installations and a very great difficulty in ensuring the processing line economical operation and sufficient profitability.

The Applicant has already proposed a method making it possible to improve the overall profitability of such a treatment line. This known method does not eliminate the incompatibility which has just been mentioned, but it makes it possible to reduce the pickling costs so as to compensate for the cost resulting from the insufficient profitability of rolling with the tandem train. To this end, this known method includes a partial descaling operation of the strip and standardization of the thickness of the residual scale layer.

The present invention relates to a device for carrying out the above operation.

More specifically, it relates to the combination of means, most of which are known separately, but whose original arrangement makes it possible, under the best conditions, to carry out the double operation mentioned above, namely partial descaling and standardization of the thickness of the residual scale layer.

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To this end, the device for mechanical descaling of a metal strip which is the subject of the present invention is essentially characterized in that it comprises in combination: - at least one strip deflection assembly, consisting of two support cylinders on which a working cylinder rests, - at least one brush, preferably a rotary brush arranged substantially opposite the contact zone between a working cylinder and the strip, so that its axis

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"4 - 3 - rotation is parallel to the axis of the corresponding working cylinder; - In the vicinity of at least one working cylinder, a nozzle, preferably a water nozzle, oriented towards the contact zone between said working cylinder and the strip; at least one roller for guiding the strip upstream from the first deflection assembly; - At least one guide roller of the strip downstream of the last set of deflection, - the expressions "upstream of the first set" and "downstream of the last set" referring to the direction of travel of the strip.

According to a preferred embodiment of the invention, the device comprises several sets of deflection of the strip, arranged so as to apply to the strip a deformation by alternating bending during its passage through the device.

Also according to the invention, the device comprises a brush opposite each working cylinder; these brushes are preferably rotated in the same direction as the working rolls. These brushes are advantageously provided with means' making it possible to adjust the pressure they exert on the strip and / or their angular position relative to the corresponding working cylinder.

Still according to the invention, the device comprises at least one nozzle in the vicinity of each working cylinder.

For the purposes of the invention, the term “nozzle” should be understood to mean an apparatus for projecting a liquid or a gas, constituted in particular by a single slot extending transversely with respect to the strip, or by a series of nozzles distributed according to * - 4 - the width of the strip. The flow of the liquid or gaseous agent projected by these nozzles may not be uniform over the entire width of the strip.

According to the invention, each nozzle is advantageously arranged, relative to the strip, on the same side as the brush with which it is associated; it is preferably placed downstream of the corresponding brush and directed towards the contact zone between the brush and the surface of the strip.

According to a particularly advantageous implementation, the device of the invention comprises a tank which contains a liquid agent, in which at least a part of the deflection assemblies of the strip are immersed to a sufficient depth so that their working rolls are entirely submerged.

In this case, the dit.agent liquid is advantageously water, optionally containing in solution and / or in suspension substances promoting the removal of scale.

In this implementation, the contact zones between the brushes and the surface of the strip are entirely submerged.

Likewise, the nozzles are immersed and they are advantageously supplied by means of the said liquid agent taken from the tank and possibly filtered.

It may also be advantageous to orient the nozzles obliquely towards the edges of the strip, in order to more easily remove the loose scale from the strip.

When passing through a device in accordance with the invention, a hot-rolled steel strip is subjected simultaneously to a tensile force which ensures its progression and to bending forces during its passage over the cylinders of work. This ensures the decohesion of a part of the surface layer of oxides, the scale, which is then mechanically detached by the brushes and / or the nozzles.

Is the removal of the detached scale easier when the operation takes place underwater? this technique has the additional advantage of eliminating any release of oxide dust 9 and of reducing noise in the vicinity of the descaling installation.

By way of simple illustration, the attached figure shows, not to scale, a device for mechanical descaling under water of a steel strip, in accordance with the invention.

A tank 1 contains an aqueous bath 2 in which are immersed four deflection assemblies 3. Each deflection assembly consists of two support cylinders 4 and a working cylinder 5 of small diameter. Each working cylinder 5 is associated with a rotary brush 6 rotating in the same direction as the corresponding working cylinder. The strip 7 to be descaled enters the bath and is directed towards the deflection assemblies 3 by a first guide roller 8. It passes successively between each working cylinder and the corresponding brush and exits the bath via a last roller guide 9.

Each rotary brush 6 is associated with a nozzle 10, directed towards the contact zone between the brush and the surface of the strip. These nozzles can be fed from the aqueous bath, by a system not shown. The tank 1 is preferably provided with an inclined bottom 11 to facilitate the collection of scale particles. It can also be equipped with a system, not shown, for evacuating the collected scale.

Claims (7)

1. Mechanical descaling device for a metal strip, characterized in that it comprises: a) at least one deflection assembly preferably made up of two support rollers and a working cylinder, b) at least one brush, preferably a rotary brush, disposed substantially opposite the contact zone between a working cylinder and the strip, so that its axis of rotation is parallel to the axis of the corresponding working cylinder, c) in the vicinity at least one working cylinder, at least one nozzle oriented towards the contact zone between the working cylinder and the strip, d) at least one roller for guiding the strip upstream from the first deflection assembly; e) at least one guide roller of the strip downstream of the last deflection assembly. 2. Device according to claim 1, characterized in that it comprises at least two deflection assemblies and in that these are arranged head to tail, so as to subject the strip to alternating bending. " 3. Device according to either of Claims 1 and 2, characterized in that the brushes are provided with means making it possible to adjust the pressure which they exert on the strip and / or their angular position relative to the cylinder of Corresponding work. 4. Device according to either of claims 1 to 3, characterized in that the nozzles are distributed along the corresponding working cylinder, certain nozzles being able to be oriented obliquely with respect to said cylinders. work, and preferably towards the edges of the strip. 5. Device according to either of claims 1 to 4, characterized in that it comprises a tank containing a liquid agent, and in that the said deflection assemblies or at least some of them, are immersed in said liquid agent to a depth sufficient for their working cylinders to be fully submerged. " 6. Device according to claim 5, characterized in that said liquid agent is water, optionally containing in solution and / or in suspension, substances promoting the removal of scale. 7. Device according to either of Claims 5 and 6, characterized in that the nozzles are supplied by means of said liquid agent. Drawings ï ....... Λ— plate ^ ___ $ ______ pages of which ............. cover page ........ 5 ....... pages of description ......... 0 ...... pages of claim ...... abstract descriptive Luxembourg, le 3 0 Ma, The representative: Me Alain flßkavi ^ a / IW