EP2750813B2 - Reversing mill and operating method for same - Google Patents

Description

Technical area

The invention relates to an operating method for a reversing, with at least one Reversierwalzgerüst for rolling a rolling stock, wherein the rolling passes in a sequence of stitches with alternating passage direction, the at least one Reversierwalzgerüst and is wound after each stitch by means of acting as a recoil reversing. The invention also relates to the use of a reversing mill according to said operating method.

A generic method is eg off JP-A 62009707 known.

State of the art

In a reversing stand or reversing stand, the rolling stock is reduced in thickness in a reciprocating sequence in a sequence of stitches. In known cold rolling plants usually an oil-water emulsion with an oil concentration of about 0.5% to 5% is used for roll-gap lubrication, roll cooling and roll cleaning. If the oil concentration is increased, the lubricating effect generally increases, that is, the friction in the roll gap is lower, while the cooling effect decreases.

Approximately 1/3 of the amount of emulsion per framework is applied to the work rolls or to the metal strip just upstream of the roll gap in the case of tandem mills for roll gap lubrication. The remaining 2/3 are used on the outlet side primarily for cooling the work rolls but also for roll cleaning, in particular for cleaning the support rollers.

In the case of a reversing stand, the total amount of emulsion per stand is generally applied on the work rolls or on the strip immediately before the roll gap on the upstream side.

Depending on the installed engine power of the main drives, the volume flow in a cold rolling mill is, for example, 0.8 l per minute and kilowatt-hour drive power. This means, for example, with a framework drive power of 6000 kW per scaffold, a volume flow of the cooling-lubricating medium (emulsion) of 4800 l per minute.

Despite this large amount of lubricant, the required amount of lubricant can be adjusted insufficiently in the nip. Namely, there is the problem that the amount of oil provided in the nip for nip lubrication is dictated primarily by the cooling requirements and not by the current lubrication requirements in the nip. It can be assumed that with emulsion lubrication in the nip, the oil concentration is well below 100%, which leads to a reduced lubricating effect. In practice, this means that the rolling oil consumption is significantly higher than the actually required amount of lubricant for lubrication of the roll gap. A targeted influence on the current lubrication and friction conditions is limited in this way possible, for example only on the oil concentration in the emulsion or additives.

In the WO 2005/115651 A1 Therefore, it is proposed to introduce only base oil without water as a carrier medium in the nip. Since the lubricant is applied to the rolling stock before entering the nip, a corresponding amount of lubricant is necessary for a uniform application.

Presentation of the invention

The invention is based on the object to provide an operating method for a reversing, in which while maintaining a good roll gap lubrication of the rolling oil consumption can be further reduced.

This object is achieved by a reversing mill with the features of claim 6 and by an operating method for a reversing mill with the features of claim 1.

According to a basic concept of the invention, the lubricant is not supplied to the inlet side of the roll gap, but the rolling stock is oiled in a previous step during coiling. As a result, the lubricant is squeezed by the superimposed layers and made uniform, so that the amount of lubricant can be further reduced. The uniform surface application of the lubricant ensures that, despite the small amount of lubricant, sufficient lubrication in the roll gap is possible. Viewed in the axial direction of the work rolls rule the same friction conditions. The rolling stock therefore undergoes uniform deformation and heating. This has an advantageous effect on the surface quality of the rolling stock, since it has fewer chatter marks. Since the coolant flow is completely decoupled from the supply of lubricant, the lubrication can be better adjusted to parameters of the rolling process. Furthermore, there is the advantage that the cooling medium, e.g. Water can be supplied with a low temperature compared to an emulsion lubrication, so that the heat dissipation is better.

The conventional roller lubrication when entering the rolling stand is therefore obsolete. According to the invention, the lubricating action is ensured exclusively via the previously oiled, incoming metal strip. In general, the starting material of a Reversiergerüstes comes from a pickling (Kontibeize or Schubbeize), in which the metal strips are oiled after pickling for the purpose of corrosion protection. These oiled belts enter the reversing roll stand as input material for the first pass. After the first stitch, the metal strip is wound up on a reversing reel acting as a reel, and, provided that followed by another stitch is provided - oiled before winding.

In order to achieve a uniform lubricating effect with the lowest possible consumption of lubricant, it may be advantageous if the rolling oil is applied uniformly over the entire width of the rolling stock in the form of an atomized oil mixture. When winding the individual layers of the metal strip come into contact and cause a homogenization of the applied rolling oil. The rolling oil penetrates well into the roughness of the rolling stock and unfolds in the subsequent rolling a good lubricating effect.

In a preferred embodiment it is provided that the rolling oil is applied in a comparatively small amount of less than 200 ml per minute, preferably in a range of about 50 to 100 ml per minute.

Since you rolled in the last stitch anyway with small Stichabnahmen, it may be advantageous if no rolling oil is applied to the rolling stock before the last and / or before the penultimate stitch. As a result, the consumption of lubricant can be further reduced because the lubrication requirements are lower in the last pass. For the last stitch is usually sufficient on the metal strip from previous stitches remaining oil to ensure a low reduction in thickness still sufficient lubricating effect.

Brief description of the drawings

Figur 1

eine schematische Darstellung eines Reversierwalzwerks das aus einem Walzgerüst und zwei Reversierhaspeln besteht, im Zustand des ersten Stichs;

Figur 2

das Reversierwalzwerk gemäß Figur 1, im Zustand des zweiten Stichs;

Figur 3

das Reversierwalzwerk gemäß Figur 1, in Zustand des letzten Stichs.

To further explain the invention, reference is made in the following part of the description to the drawings, from which further advantageous embodiments, details and further developments of the invention can be found by way of non-limiting embodiment.
Show it:

FIG. 1

a schematic representation of a reversing mill consisting of a rolling mill and two reversing, in the state of the first stitch;

FIG. 2

the reversing mill according to FIG. 1 , in the state of the second stitch;

FIG. 3

the reversing mill according to FIG. 1 , in the state of the last stitch.

Embodiment of the invention

FIG. 1 shows in a simplified schematic representation of a reversing mill 1. In such a reversing mill 1, the rolling stock 5 passes through with alternating passage direction 7 of one or more rolling stands. In the present example, the reversing mill 1 consists of a single Reversierwalzgerüst 2. On both sides of this Reversierwalzgerüstes 2 each Reversierhaspel 3, 4 is arranged. Depending on the direction of movement 7 of the rolling stock 5, these Reversierhaspeln 3, 4 once as a reel, once as uncoiler. Is shown in FIG. 1 the first stitch, in which the reversing reel 3 forms a reel and the reversing reel 4 forms a reel 41. An already oiled rolled strip 5, coming for example from a pickling ago, is reduced in thickness in the nip of the Reversierwalzgerüstes 2. In this case, the rolled strip 5 in the indicated passage direction 7 from left to right, the work rolls this Reversierwalzgerüstes passed 2. How the FIG. 1 it can be seen, according to the invention, the roll gap on the upstream side of the roll stand 2, no lubricant is supplied, which on the work rolls still on the surface of the rolled strip 5. The lubricating effect is exclusively caused by the rolling strip 5 adhering to the rolling oil, which is introduced from the pickling ago becomes.

The cooling of the rolls of the roll stand 2 is carried out with a completely separate from the lubricating medium cooling medium. The cooling medium in the present example is pure water which is sprayed by means of a device 8, for example a row of nozzles, onto the rolls of the reversing roll stand 2. After the rolled strip 5 has passed through the nip, it is on the right side of the FIG. 1 wound up by means of a reversing reel 4. This reversing reel 4 acts as a reel 41. As already stated, in contrast to the prior art at the scaffold inlet neither on the rolled strip nor on the rolls of the rolling mill an emulsion for the purpose of lubrication or cooling applied. The lubricating effect is accomplished only via the incoming oiled rolling stock. The cooling is done exclusively by water, without the addition of lubricant.

The oiling of the rolling stock takes place in a step upstream of the rolling pass, in which rolling oil is applied to the rolled strip before being wound up. This is done by means of a rolling oil applicator 6, which sprays the rolling oil 9 both on the top and on the underside of the rolled strip 5. As a result, the rolling oil adheres very well to the rough surface of the rolling stock. The rolling oil may be a base oil provided with additives.

In particular, in a cold rolling process, it is important that the applied lubricating film is as uniform as possible over the entire width of the web as evenly as possible. A suitable rolling oil applicator may be of a different type, e.g. an arrangement of several nozzles in the form of a spray, nozzle or spray bar. Such devices are assumed to be known in the following and are not the subject of the present invention.

FIG. 2 now shows the second stitch following stitch one. The passage direction 7 has now reversed, that is, it runs from right to left. The two Reversierhaspeln 3, 4 now rotate in an opposite direction, that is opposite clockwise. Reversing reel 3 now acts as a reel 31. Before the rolled strip 5 is wound on the reel 31 again takes place by means of an outlet side (corresponding to the changed passage direction now left in FIG. 2 ) arranged rolling oil applicator 6, the oiling of the rolled strip 5. Here, the rolling oil 9 is applied again on both sides of the rolled strip 5. The rolling oil 9 is not mixed with a liquid carrier medium such as water. The roll cooling of the Reversierwalzgerüstes 2 is again with pure water and is separated from the lubrication in the nip.

As can be seen from the above, in the example shown here, each reversing reel 3, 4 upstream of such a rolling oil application device 6, since each of the Reversierhaspeln 3, 4 according to the respective direction of movement 7 of the metal strip 5 alternately works as a recoiler or uncoiler; in the FIGS. 1 and 2 For the sake of simplicity, only the rolling oil application device 6 which is active in the operating state shown, that is to say in operation, is shown in the drawing.

The reduction in thickness in the now following rolling passes takes place in the manner known from reversing stands by successively reducing the thickness of the rolling stock in the nip between the work rolls in the nip. These stitches of the cold rolling process are not shown in the drawings.

The last stitch is back in FIG. 3 outlined. Again FIG. 3 can be seen, the metal strip is no longer oiled in the last stitch, but the lubrication effect is achieved by the already applied in the previous or already in the penultimate stitch on the surface of the rolled strip and remaining there residual amount of rolling oil. This residual amount of lubricant is sufficient because the thickness decrease of the rolling stock 5 in the last pass is usually very low.

It is a significant advantage of the invention that the required amount of oil can be significantly reduced in a cold rolling mill. Since the media are separated for lubrication and cooling, the amount of lubricant can be adjusted depending on process variables such as belt speed, rolling force, roller roughness and so on. This differentiated adjustment of the lubrication is of great advantage.

Since the oil concentration in the nip is 100%, rolling forces and rolling moments can be reduced. This can save energy overall.

Since the lubrication is decoupled from the cooling, a coolant with a comparatively lower temperature can be used, which improves the cooling effect. As a result, the amount of water required for the cooling can be saved. By comparison, when using emulsion, the emulsion temperature must not be below about 48 ° C, otherwise fungal and bacterial growth will be favored.

Advantageously, a metastable or even unstable rolling oil is used, which has a low content of emulsifiers. The metastable or unstable rolling oil can be easily separated from the water and it must be recycled only water in the circulation loop. It is possible to reuse the oil separated from the water.

Overall, therefore, both the rolling oil consumption and the amount of coolant can be reduced. The equipment required for the preparation of the media for lubrication and cooling is relatively lower, which leads to lower investment costs and operating costs.

Although the invention has been further illustrated and described in detail by the embodiment illustrated above, the invention is not limited by the disclosed example, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

Compilation of the reference numbers used

1

reversing

2

reversing

3

reversing reel

4

reversing reel

5

rolling

6

Rolling oil applicator

7

Throughput direction

8th

Coolant application device

9

rolling oil

31

Reversible reel 3 as a reel

41

Reversible reel 4 as a reel

Claims (10)

1. Operating method for a reversing mill, comprising at least one reversing stand (2) for rolling a stock (5), wherein the stock (5) passes through the at least one reversing stand (2) in a sequence of passes in an alternating direction of travel (7) and is wound up after each pass by means of a reversing reel (3, 4) acting as a coiler (31, 41),
   characterised in that in a preceding work step the stock (5) is lubricated, prior to being wound on the coiler (31, 41), for a rolling gap lubrication in the rolling pass subordinate to the preceding work step so that the stock (5) is wound on the coiler lubricated wherein only rolling oil (9) without water as a carrier medium is applied to the stock (5) by means of a rolling oil applicator (6) disposed between the at least one reversing stand (2) and the coiler (31, 41) so that a rolling gap lubrication is produced in the rolling pass subordinate to the preceding work step solely by the rolling oil (9) applied prior to coiling.
2. Operating method according to claim 1,
   characterised in that the rolling oil (9) is applied evenly over the entire width of the stock (5) as an atomised oil/air mixture.
3. Operating method according to claim 1 or 2, characterised in that the rolling oil (9) is applied in a quantity of no more than 200 ml per minute.
4. Operating method according to claim 3
   characterised in that the rolling oil (9) is applied at between 50 and 100 ml per minute.
5. Operating method according to one of claims 1 to 4, characterised in that no rolling oil (9) is applied to the stock (5) prior to the final and/or prior to the penultimate pass.
6. Reversing mill having at least one reversing stand operated according to a method according to one of claims 1 to 5, wherein a stock (5) passes through the at least one reversing stand (2) in a sequence of passes in an alternating direction of travel (7), having reversing reels (3, 4) disposed at the entry and exit side,
   wherein a rolling oil applicator (6) for applying rolling oil (9) without water as a carrier medium is disposed between the at least one reversing stand (2) and the reversing reel acting as a coiler (31, 41), so that the stock (5) can be lubricated before it is wound on the coiler (31, 41) so that a lubricating effect is produced solely by the rolling oil (9) applied prior to coiling.
7. Reversing mill according to claim 6,
   characterised in that the rolling oil applicator (6) is designed to apply the rolling oil (9) evenly over the entire width of the stock (5) in the form of an atomised oil mixture.
8. Reversing mill according to one of claims 6 or 7,
   characterised in that the rolling oil applicator (6) is designed to apply the rolling oil (9) to the stock (5) in a maximum quantity of 200 ml per minute.
9. Reversing mill according to claim 8,
   characterised in that the rolling oil applicator (6) is designed to apply the rolling oil (9) at between 50 and 100 ml per minute.
10. Reversing mill according to one of claims 6 to 9,
    characterised in that no rolling oil (9) is applied to the stock (5) prior to the final pass and/or prior to the penultimate pass.

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