EP2722112B1 - Method and device for continuous treatment of a metal strip - Google Patents

Description

The invention relates to a device for the continuous treatment of a metal strip, in particular a metal strip of aluminum (or an aluminum alloy) or of non-ferrous metal (or a non-ferrous metal alloy), with at least one tempering, which is designed as a ribbon float furnace through which the metal strip is passed floating and with a strip running control device with which the position of the metal strip in the strip running plane and transverse to the strip running direction is controllable or controllable, wherein the strip float oven has at least one inlet side heating section and an outlet side cooling section. The metal strip preferably has a thickness of 0.1 mm to 6 mm.

The tempering device is a ribbon float furnace having a heating section and a cooling section. The heating section usually consists of several heating zones (heating or holding zones) and the cooling section usually consists of several cooling zones. In such a tempering device, the metal strip is heated to a determined (setpoint) temperature, if appropriate kept at this temperature for a specific time and then cooled again. The passage through the furnace is non-contact, by the band between nozzles (air nozzles), which are acted upon by corresponding air pressure, floated. The cooling in the cooling zones can be done by air, water or a combination of air and water. Such strip-type furnaces with heating section on the one hand and cooling section on the other hand are known (cf. DE 198 04 184 A1 ).

The DE 103 26 071 discloses a device for the continuous treatment of a metal strip, with at least one tempering device through which the metal strip is passed floating and with a band position control device with which the position of the metal strip in the strip running plane and transverse to the strip running direction is controlled or regulated, wherein the tempering at least one inlet side Has heating section and an outlet-side cooling section.

In such a device of the type described above for the continuous treatment of a metal strip with a tempering device or with a ribbon float oven, it may be, for. B. an annealing line or Kontiglühlinie act, in which the metal strip undergoes a heat treatment for metallurgical reasons, for. B. to achieve certain strength and deformation properties. Alternatively, however, the device may also be a strip coating line or a strip coating line in which the heat treatment of the metal strip does not take place in the sense of annealing, but for drying a coating of a strip, so that the oven is then designed as a continuous dryer.

The metal strip is preferably aluminum or non-ferrous metal strip in a thickness range of 0.1 mm to 6 mm.

Since the metal strip z. B. is heated in annealing lines to temperatures near the melting point, it is usually necessary to adjust within the tempering a relatively low band tension to avoid a band break. For this purpose, the strip tension z. B. degraded on the inlet side in a clamping roller set and the outlet side after cooling again built in a further set of clamping rollers. In the tempering device (ribbon float furnace) the specific strip tension is z. B. 0.5 to 1 MPa. Since the tape can "run" in particular with low tape tension in the oven, z. B. due to eventual bandsaw, it is necessary to position the band by means of a belt position control device in a suitable manner, preferably to bring the center of the tape. The positioning is thus carried out in the strip running plane transversely to the strip running direction. Such a strip-guiding device generally has at least one control roller and suitable position-measuring devices, for. B. band edge detections on. In the systems known from practice, the strip running control device behind the tempering, that is arranged after the cooling section. The control role is usually carried out in practice as so-called PI band center control, ie with a proportional P and an integral I component. The I component acts in the furnace section back and prevents too much bleeding of the tape in the oven. As a rule, the control roller sits on a movable base frame. This rotates the roller about an imaginary pivot point or about an imaginary axis of rotation, which lies in the furnace section and is perpendicular to the strip running plane. The degree of displacement of the roller from the center axis of the furnace section is the proportional component, the extent of the misalignment of the roller the integral component of the belt center control. In an oblique role, the band wanders by the so-called winding effect back towards the center of the band. Such systems known from practice have basically proven themselves.

A plant of the type described above is z. B. from the DE 103 37 502 B4 known. An oven with heating zones and cooling zones is adjoined by a deflection pulley serving as the center of the belt.

Incidentally, from the DE 103 26 071 A1 a system is known in which the outlet side behind a ribbon float furnace, a deflection device is arranged, below which there is a water cup as a fluid seal. At the same time, the deflection can also be used to control the center of the strip, wherein the band position is detected by sensors arranged above and below the band and the movement of the band center control for returning a band extending from the center layer by means of a cylinder.

In practice, due to the rapidly growing demand for aluminum body manufacturers, there is a need to build more and more efficient annealing lines. To achieve higher production capacity, the belt passes through the treatment section at a higher speed. However, since only a limited heat input can be brought into the band per oven zone, it follows that the temperature control device would have to be designed longer for a higher production capacity. Because the band because of the If the low strip tension in the furnace section is easier, there is the risk with large furnace lengths that the known belt position control devices are no longer sufficient to keep the strip running in the furnace stable, so that there is a risk that the strip runs laterally or starts against the furnace construction. This can lead to undesired tape damage or a tape break, so that plants with increased production capacity can not be realized in this way easily. - This is where the invention starts.

The invention has for its object to provide a device for the continuous treatment of a metal strip of the type described above, which is characterized by an improved band position control and guarantees a perfect tape especially in long kiln lines.

To solve this problem, the invention teaches in a generic device for the continuous treatment of a metal strip, that the band position control device is disposed within the cooling section. For this purpose, the cooling section is preferably divided into at least one first cooling section section and a subsequent spaced second cooling section section, wherein the band position control device is arranged between the first cooling section section and the second cooling section section. According to the invention, the band position control device is consequently no longer arranged on the output side behind the temperature control device and consequently no longer after the last cooling zone, but rather it is integrated into the cooling path, as it is preferably divided into two cooling path sections. In a first section, the belt is cooled down so far that it can easily pass through the belt control device. Following the first cooling section, therefore, the band position control device is located. Subsequently, the band passes through the second cooling section and thus the second part of the Cooling zones, so that the band is then cooled down to the desired final temperature. In this way, a total of a long kiln line and consequently with long heating sections and cooling sections can be used, so that the production capacity is increased, without the free band length must be increased significantly in the range of low strip tension. In this way, an impermissible belt run in the oven is reliably avoided.

The tape position control device itself can be designed in a conventional manner, it can therefore be resorted to conventional solutions. According to the invention, it depends on the particular positioning of the strip running control device within the furnace section or within the cooling section.

Thus, the band position control device for the band position control z. As a conventional, adjustable pulley, z. B. have a 90 ° -Umlenkrolle or be designed as such. However, it is advisable to provide the deflection roller with a suitable (high) temperature-resistant coating, since the belt temperature between the first cooling section and the second cooling section is preferably 100 ° C to 200 ° C, particularly preferably 120 ° C to 150 ° C. As an alternative to a 90 ° control roller can also be on another known type of band center control, z. B. using a multi-role control device, for. B. a three-roller control device or a control driver (eg., As a pair of rollers) are worked. Also in this case, suitable coatings are preferably provided. Preferably, the band position control or band center control is performed in a basically known manner as a PI control. The control roller or the multi-roller assembly thus sits in a basically known manner on a movable base frame. This twists the role or the roles around an imaginary fulcrum, which in turn in the Furnace section is located. The degree of displacement of the roller from the center axis of the furnace section is the proportional component, the extent of the misalignment of the roller the integral component of the belt center control.

Alternatively, the band position control device can be designed as a non-contact band position control device. For this purpose, the band center control z. B. done contactlessly via linear motors. In principle, recourse can be had here to known arrangements for influencing the metal strip by means of linear motors, which are described, for example, in US Pat DE 197 19 994 A1 to be discribed.

Preferably, the belt treatment plant on the inlet side on a first set of tension rollers, which is arranged in front of the temperature control to reduce the strip tension. Furthermore, it is expedient to provide on the output side and thus behind the tempering a further set of tension rollers, with which the strip tension is increased again, so that can join further process steps, such as. B. straightening, cleaning or edge trimming.

Optionally, it is within the scope of the invention that a (further) tensioning roller set is arranged between the first cooling section section and the second cooling section section behind the belt position control device in order to increase the belt tension already at this point. This has the advantage that the band can pass through the second part of the cooling zones with a slightly increased strip tension. Also in this case it is expedient to provide the rollers of such a roller set with appropriate temperature-resistant coatings. According to the invention, it is important that a band position control takes place between the first cooling section section and the second cooling section section. Optionally, it may be appropriate to behind the second cooling section section to provide a further band position control. This may be particularly useful if between the first cooling section and the second cooling section section no additional tensioning roller set is provided and consequently also worked in the second cooling section section with a lower strip tension. If a tensioning roller set is provided between the two cooling sections and consequently the strip tension is already increased at this point, it may be possible to dispense with a second strip position control behind the second cooling section.

The division of the cooling section into two cooling sections has the consequence that the two cooling sections are (significantly) shorter than a corresponding uniform cooling section. Compared to conventional systems can be extended in this way, the entire tempering, d. H. Both the heating section can be extended and the entire cooling section.

The invention also provides a process for the continuous treatment of a metal strip with a device of the type described, wherein the metal strip for thermal treatment is guided floating through the heating section and the cooling section. This method is characterized in that the position of the metal strip (within the strip running plane and transversely to the strip running direction) is controlled or regulated by means of a strip position control device arranged inside the cooling section.

As already described, such a band position control device is preferably equipped with suitable measuring devices and a feedback, so that a real regulation of the band position takes place. In principle, however, the invention also covers embodiments in which without measurement and / or without Return is worked so that no regulation of the band position, but only a control is done.

Preferably, the length of the first cooling section is dimensioned such that the metal strip between the first cooling section and the second cooling section and thus in the region of the band position control device a temperature of up to 200 ° C, z. B. 100 ° C to 200 ° C. More preferably, the temperature is up to 150 ° C, z. B. 120 ° C to 150 ° C. The length of the second cooling section can then z. B. be sized so that the tape with a temperature of up to 70 °, preferably up to 60 ° C z. B. 40 ° C to 60 ° C, so that easily further process steps, such. B. straightening, cleaning or edge trimming can follow.

The inventive system can, for. B. be designed as annealing line or be part of an annealing line. The tempering device is then designed as an annealing furnace. Alternatively, the system can be designed as a coil coating system or be part of a coil coating plant. The tempering device is then designed as a dryer or dryer oven. In both cases, the ovens / dryers are preferably designed as a ribbon float oven.

Fig. 1

eine bekannte Bandbehandlungsvorrichtung nach dem Stand der Technik in einer vereinfachten schematischen Darstellung,

Fig. 2

eine erfindungsgemäße Bandbehandlungsvorrichtung in einer vereinfachten schematischen Darstellung und

Fig. 3

eine abgewandelte Ausführungsform des Gegenstandes nach Fig. 2.

In the following the invention will be explained in more detail with reference to drawings showing merely exemplary embodiments. Show it

Fig. 1

a known prior art belt treatment apparatus in a simplified schematic representation,

Fig. 2

a strip treatment device according to the invention in a simplified schematic representation and

Fig. 3

a modified embodiment of the article according to Fig. 2 ,

In order to clarify the concept of the invention, it is expedient, first again according to the prior art Fig. 1 consider. Fig. 1 shows a known belt treatment apparatus for the continuous treatment of a metal strip, namely a thermal treatment. This device has a tempering 2, which is designed as a ribbon float furnace. The metal strip 1 passes through this strip float furnace 2 without contact by the strip between the upper nozzles and lower nozzles, which are acted upon by corresponding air pressure, is moved without contact. Details are not shown. The strip float furnace 2 has a heating section 3 on the inlet side and a cooling section 4 on the outlet side. The heating section is generally composed of a plurality of heating zones 3 ', while the cooling section is generally composed of a plurality of cooling zones 4', wherein the individual zones are individually or separately controllable. In the heating zones, the heating of the metal strip is usually done by means of the air, so that the nozzles, z. B. the lower nozzles in addition to the support function can also take the temperature. In the cooling zones, the cooling is usually also done by air or by a combination of air and water. In the case of an annealing line for aluminum bands for automotive bodywork purposes, the target temperature in the heating zone is z. B. about 550 ° C to 570 ° C. The heating zones thus form heating and holding zones. It can be seen that the system on the inlet side has a tensioning roller set 5, with which the strip tension is reduced, for. B. on a specific strip tension of z. B. 0.5 to 1 MPa. After the strip float furnace 2 or after the last cooling zone, the metal strip 1 is center-controlled by means of a belt position control device 7, ie the position of the metal strip is regulated in the strip running plane and transversely to the strip running direction. Subsequently, the strip tensioner with an outlet side pulley set 6 back to the usual line level of z. B. specifically increased 10 to 20 MPa. Because of the low specific strip tension within the strip float furnace, it is necessary to bring the metal strip 1 to the center of the strip by means of the strip position control device 7.

Do you want the production capacity of such in Fig. 1 increase shown system, it is generally necessary to extend the ribbon float furnace. With the in Fig. 1 shown system consists of the risk that the band position control device 7, z. B. the control roller 8, is no longer sufficient, so that the tape can be unstable in the oven, so the tape runs laterally, or starts at the furnace construction. This could lead to unwanted tape damage or a tape break, so that a simple extension of the ribbon float furnace is not appropriate without further measures.

According to the invention, therefore, the band position control device 7 is no longer located behind the temperature control 2 and therefore no longer behind the cooling section 4, but within the cooling section 4 itself. This is based on the Fig. 2 and 3 explains which embodiments of the invention show. The Fig. 2 and 3 again show a strip processing apparatus with a temperature control device 2, which has an inlet-side heating section 3 and a downstream cooling section 4. On the inlet side, in turn, a tensioning roller set 5 is provided and on the outlet side, in turn, a further tensioning roller set 6 can be provided, which is only in Fig. 3 but not in Fig. 2 is shown. The heating section 3 is in turn composed of several heating zones 3 ', while the cooling section 4 is composed of a plurality of cooling zones 4'. According to the invention, the cooling section 4 is divided into two cooling section sections, namely a first cooling section 4a and a subsequent second cooling section 4b. The belt positioner device 7 is now arranged according to the invention between the first cooling section 4a and the second cooling section 4b. The metal strip is heated in the heating section 3 with the heating and holding zones 3 'in a basically known manner to the desired temperature and the temperature can be maintained for a desired time. Consequently, apart from an extension, the heating section 3 does not have to be modified compared with the prior art. The heating section 3 is then followed by the first cooling section 3a, with which the metal strip is cooled down in a first stage, preferably to a temperature of 100 ° C to 200 ° C, z. B 120 ° C to 150 ° C. After leaving the first cooling section 4a, the strip center is controlled by means of the strip center control device 7. In the embodiment according to Fig. 2 this has a 90 ° control roller 8. This is followed in the exemplary embodiment Fig. 2 another tension roller set 9 to increase the tape tension. Thereafter, the band passes through the second cooling section 4b, so that it reaches the desired final temperature of z. B. 40 ° C to 60 ° C is cooled down. In this way, it is possible to increase the production capacity without appreciably prolonging the free tape length, so that an impermissible belt run in the furnace is avoided. At the second cooling section 4b may be followed by another band position control device and / or another set of tensioning rollers. This is in Fig. 2 not shown.

Fig. 3 shows a modified embodiment of the invention, in which the strip center control device 7 is designed as a three-roller belt center control with three rollers 10. Furthermore, in Fig. 3 indicated that behind the second cooling section 4b, a further strip center control device 11 and a further set of tension rollers 6 may be arranged. The additional midband control 11 behind the second cooling section 4b is therefore useful because in this embodiment between the cooling sections 4a, 4b no tensioning roller set is arranged and therefore also in the second section 4b is operated with a lower strip tension.

If you compare z. B. the Fig. 1 and 2 , it can be seen that the furnace zones 3 ', 4' in the embodiment according to the invention overall have a length which is greater than the length in the known embodiment according to Fig. 1 , Nevertheless, the free tape length is not greater, since the mid-band control 7 is already connected to the first cooling section 4a. This allows both the heating section 3 and the cooling section 4 over the prior art significantly extend. However, due to the division of the cooling section 4, cooling section sections 4a, 4b are formed which are each (significantly) shorter than the heating section 3.

Claims (12)

1. Device for continuous processing of a metal strip (1), particularly a metal strip made of aluminium or an aluminium alloy, or of non-ferrous metal or a non-ferrous metal alloy,
   having at least one thermal treatment apparatus, which is in the form of a strip flotation furnace (2) through which the metal strip (1) is floated,
   and having a strip position adjustment device (7), with which the position of the metal strip (1) can be controlled or adjusted in the strip running plane and transversely to the direction of advance of the strip,
   wherein the strip flotation furnace (1) has at least one heating line (3) on the infeed side and one cooling line (4) on the outfeed side,
   characterised in that
   the strip position adjustment device (7) is arranged in the cooling line (4).
2. Device according to claim 1, characterised in that the cooling line (4) is divided into at least a first cooling line section (4a) and a second cooling line section (4b) downstream therefrom, wherein the strip position adjustment device (7) is arranged between the first cooling line section (4a) and the second cooling line section (4b).
3. Device according to either of claims 1 or 2, characterised in that a further strip position adjustment device (11) is arranged after the second cooling line section.
4. Device according to any one of claims 1 to 3, characterised in that the strip position adjustment device (7, 11) comprises a movable deflection roller (8), for example a 90° deflection roller, or has the form of such for adjusting the position of the strip.
5. Device according to any one of claims 1 to 3, characterised in that the strip position adjustment device (7, 11) is in the form of a multi-roller assembly, for example a three-roller device.
6. Device according to any one of claims 1 to 5, characterised in that the strip position adjustment device (7, 11) is designed as a device that functions without contact, for example with linear motors.
7. Device according to any one of claims 1 to 6, characterised in that a tension roller assembly (11) located downstream from the strip position adjustment device (7) is arranged between the first cooling line section (4a) the second cooling line section (4b).
8. Device according to any one of claims 1 to 7, characterised in that the rollers (8, 9) of the strip position adjustment device (7) and/or of the tension roller assembly (11) are furnished with a thermally resistant coating.
9. Method for continuous processing of a metal strip using a device according to any one of claims 1 to 8, wherein the metal strip is passed in floating manner through the heating line and the cooling line to undergo thermal processing, characterised in that the position of the metal strip is controlled or adjusted with a strip position adjustment device arranged in the cooling line.
10. Method according to claim 9, characterised in that the strip position adjustment device is arranged between a first cooling line section and a second cooling line section.
11. Method according to either of claims 9 or 10, characterised in that strip position is adjusted with a PI control having a proportional P-component and an integral I-component.
12. Method according to any one of claims 9 to 11, characterised in that the strip position adjustment device is arranged in an area of the cooling line, for example between the first cooling line section and the second cooling line section, in which the temperature of the metal strip reaches up to 200°C, for example 100°C to 200°C, preferably up to 150°C, for example 120°C to 150°C.

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