EP2384829A1 - Method of and device for removing coolant and/or lubricant from rollers of a roller framework according to a use parameter of the rolling process - Google Patents

Abstract

The method involves conveying a rolled strip (14) through a rolling gap (13) formed between work rollers (12) in the strip running direction (15), and fitting a scraping unit (20,21) with a scraping edge (25,26) on an inlet side or an outlet side of the rolling mill (10) with contact pressure against a rolling surface (24) of the work roller or a support roller (16,17) supporting the work roller in the rolling mill. The contact pressure is changed corresponding to the operating parameter of the rolling process. An independent claim is also included for a device for removing coolant and lubricant of rollers of a rolling mill.

Description

The present invention relates to a method for removing coolant and / or lubricant from rolls of a roll stand, in which a rolled strip is conveyed through a roll gap formed between work rolls in the strip running direction, wherein at least one stripping device on an inlet side and / or an outlet side of the rolling stand with a scraping edge with contact pressure against a roll surface of a work roll or a work roll supporting the roll stand in the roll stand. Moreover, the invention relates to a device for carrying out the method.

For cooling or lubrication of the roll surfaces of working and / or back-up rolls, rolling stands in which the aforesaid rolls are arranged are provided with means for allowing the roll surfaces to be exposed to coolant and / or lubricant. So it is for example from the EP 1 399 277 A1 It is known to provide the rolling mill with means for allowing the roll surface of the work rolls to be loaded with lubricant. Below this facility, also called a lubricant bar is designated, there is a scraper, with which is to be prevented that lubricant passes as a result of the roll rotation of the inlet side of the rolling mill on the outlet side of the rolling mill and there forms a lubricant occupancy of the rolled strip surface.

In principle, an outlet-side surface covering of the rolled strip surface with lubricant is to be avoided, since a considerable outlay is associated with the removal of this surface covering. In practice, it has hitherto been regularly necessary to remove a removal of corresponding lubricant residues on the rolled strip surface by means of an annealing treatment of the rolled strip following the rolling process. This is associated with a significant energy demand, which makes up a corresponding proportion of the production costs of the rolled strip.

With the known Abstreifervorrichtungen an outlet side occupancy of the rolled strip surface with lubricant should be reduced as much as possible in order to reduce the subsequently operated degreasing effort, for example by annealing, according to.

In practice, therefore, it has begun to press the stripping devices, which are designed as so-called wiper lips under pressure against the roll surface of the respective rollers, with such a high contact pressure against the roll surfaces, that an effective stripping of lubricant is ensured by the roll surface. The contact pressures set are often so high that increased wear of the wiper lips occurs. In addition, due to the constant set contact pressure, which is to allow independent of the roller speed in each case a safe stripping, at very low rolling speeds, ie in particular when starting the rolling and braking the rollers, whistling or squeaking, which is a significant noise emission represent.

The operator of the rolling stands is therefore often on, during the acceleration and deceleration of the rollers in the rolling stand, the wiper lips do not rest against the roll surface, with the result that during these phases increased oil deposits on the outlet side arise. This unsteady oil occupancy of the rolled strip surface causes due to the subsequent annealing on the rolled strip surface often form discolorations that make corresponding rolled strip sections to committee.

The present invention is therefore based on the object to propose a method or a device which reliably contributes to a largely avoidance of oil occupation of the rolled strip surface on the outlet side of a rolling stand.

This object is achieved by a method having the features of claim 1.

In the method according to the invention for degreasing the coolant and / or lubricant of rolls of a roll stand, the contact pressure with which the scraping edge of the stripper abuts against a roll surface of a work roll or a support roll supporting the work roll in the rolling stand is changed as a function of an operating parameter of the rolling process , Depending on the design and / or the material of the scraper, it is not always necessary to form a scraper edge, so that in the corresponding cases, a rather flat contact of the scrapers against the roll surface in the sense of a scraper surface can be formed. The term "wiper edge" is therefore not to be understood as limited in that a line contact is formed between the wiper and the roller surface in each case.

In this operating parameter, which affects the action of the stripping, it is preferably the roller peripheral speed at which the respective rollers, ie the rollers against which abuts the wiper, rotate. Apart from that, it can of course also be other operating parameters, in particular the temperature of the respective roller or roller surface, the roughness or crowning of the roller surface. Operating parameters are thus to be understood as all parameters influencing the rolling process or the result of the rolling process, which at the same time also have an effect on the effectiveness of the stripping device.

However, the positive effect of a change in the contact pressure becomes particularly immediately apparent if this change takes place as a function of the peripheral roll speed. The use of the parameter "roll peripheral speed" as a control variable for a corresponding Andrucksteuerung or pressure control, based on the finding that, for example, in a start-up, so at relatively low roller peripheral speed, a correspondingly low contact pressure is sufficient to achieve a secure wiping effect. On the other hand, it is necessary at higher roller circumferential speed to increase the contact pressure in order to prevent, for example, aquaplaning effects, ie, a floating of the stripping device on a lubricant film formed on the roller surface. The consequence of such floating is namely that the lubricant can pass the stripping device in an undesired manner and thus reach the outlet side of the rolling stand and thus the outlet side rolled strip surface.

Considering the entire rolling process, so starting with a start-up phase to a deceleration phase following a stationary operating phase in which the rollers rotate in the rolling mill at a constant speed, it proves to be particularly advantageous in practice, when an increase in the roller peripheral speed of Increased contact pressure and with a reduction in the roller circumferential speed of the contact pressure is reduced accordingly.

In principle, it is possible to proceed in such a way that fixed pressure steps are used with regard to the setting of the contact pressure, although it proves to be particularly advantageous if a continuous change in the contact pressure occurs as a function of the roller circumferential speed.

In particular, in order not only to include operating parameters of the mill stand, but also operating parameters of other aggregates and devices involved in the rolling process, it proves to be advantageous if a material or shape parameter of the stripping device is used as a further parameter when changing the contact pressure. For example, it is possible to take into account the elasticity of the scraping edges when changing the contact pressure.

A further optimization of the method can take place if a material or shape or surface parameter of the roller cooperating with the stripping device is used as a further parameter in the change of the contact pressure, so that it is also conceivable, for example, depending on a roll crown form the contact pressure acting along the roll axis of the wiping edge on the roll surface differently.

Furthermore, it may prove advantageous if, as a further parameter in the change of the contact pressure, a parameter determined by the coolant / lubricant is used. For example, such parameters may be due to the nature or the composition of the lubricant or in the amount of lubricant, so that about the contact pressure is changed in further dependence on the viscosity of the lubricant.

A further increase in the effectiveness of the stripping device can be achieved if, during a rolling break in which the actual production process, in the rolled strip through the nip is conveyed is exposed, the stripping device is cleaned by means of a stripping device associated cleaning device.

For example, a cleaning medium can be applied to the stripping device or in particular the stripping edge of the stripping device by means of the cleaning device assigned to the stripping device during the rolling break. For this purpose, a suitably aligned air flow or a liquid detergent may already be suitable. As the cleaning agent can be advantageously used the same medium as for lubricating and / or cooling the rollers. By means of a corresponding cleaning device, in particular so-called "rolling flakes" or abrasion originating from the rolled strip, can thus be removed from the wiping edge in order to provide a surface for the stripping process which is freed from corresponding impurities during production.

It proves to be particularly advantageous if, during cleaning, the wiping edge, in addition to being exposed to the wiping edge, is acted upon by a cleaning medium with mechanical oscillations, which enable a gravity cleaning of the wiping edge.

The device according to the invention has the features of claim 12.

In the apparatus according to the invention a stripping device associated pressing device is provided which has at least one pressing means for acting on the stripping with a compressive force, such that the stripping edge of the stripping abuts with a contact pressure against the roll surface of the work roll or a work roll in the roll stand supportive support roller wherein the pressure device is associated with a control / regulating device which acts on the pressing means in response to an operating parameter of the rolling process with a manipulated variable, in such a way that the scraping edge bears against the roll surface with a defined contact pressure.

This manipulated variable may be formed, for example, as a path, pressure or as electrical voltage, which changes depending on the operating parameters, so for example, the roller peripheral speed.

For the effectiveness of the stripping, it has been found to be particularly advantageous if the stripping device is arranged on the rolling mill, that it cooperates with the upper and / or lower support roller.

A further increase in effectiveness can be achieved if the rolling stand is provided on both the inlet side and on the outlet side with one of the upper and / or lower support roller associated scraper.

If the stripping device has at least one scraper, which has a rectangular profile and is received at an angle of attack to the strip running direction in the stripping device, such that the stripping edge is formed by a longitudinal edge of the scraper, on the one hand an easily reproducible scraper edge is formed. On the other hand, four stripping edges are thus provided by only one scraper.

Such a multiple formation of scraping edges on only one scraper can be used particularly advantageously when the scraper is exchangeably received in the stripping device, such that by suitable turning operations of a scraper successively all four stripping edges are available.

It is particularly advantageous if, in order to maintain the effectiveness of the stripping device, the stripping device is provided with a cleaning device.

This cleaning device may be provided with means for acting on the stripping device or the stripping edge with a cleaning medium, wherein preferably in addition to the cleaning means in addition to means for loading the scraping edge with a cleaning medium comprises a vibration generator, the stripping in mechanical vibrations or movements, preferably in the roll axis direction or in the longitudinal direction of the scraper, offset. For example, the vibration generator may have a scraper device with reciprocating eccentric drive in the longitudinal axis direction of the stripping device or the respective roller.

Fig. 1:

die Einlaufseite eines Walzgerüstes mit einem einer Stützwalze zugeordnetem Abstreiferaggregat;

Fig. 2:

eine Frontansicht des in Fig. 1 dargestellten Abstreiferaggregats;

Fig. 3:

eine Schnittdarstellung des in Fig. 2 dargestellten Abstreiferaggregats längs Schnittlinienverlauf III-III in Fig. 2 ;

Fig. 4:

eine Schnittdarstellung durch eine Reinigungseinrichtung der im Abstreiferaggregat angeordneten Abstreifeinrichtung längs Schnittlinienverlauf IV-IV in Fig. 2

Hereinafter, a preferred variant of the method will be explained with reference to the operation of an embodiment of the device with reference to the drawing. Show it:

Fig. 1:

the inlet side of a roll stand with a backing roll associated Abstreiferaggregat;

Fig. 2:

a front view of the in Fig. 1 shown Abstreiferaggregats;

3:

a sectional view of the in Fig. 2 shown Abstreiferaggregats along section line III-III in Fig. 2 ;

4:

a sectional view through a cleaning device of the scraper arranged in Abstreiferaggregat along section line IV-IV in Fig. 2

Fig. 1 shows a rolling stand 10 with two work rolls 11, 12 between which a roll gap 13 is formed, through which a rolled strip 14 is conveyed in the direction of strip 15. The work rolls 11, 12 are arranged between two support rolls 16, 17, which are comparatively rigid with respect to the work rolls 11, 12 and support the latter along their bending line to a substantially constant nip 13 over the length of the work rolls 11, 12 form.

As in further Fig. 1 shown, located on an inlet side 18 of the rolling stand 10, a scraper unit 18 which is arranged in a machine frame 19 and is in the present case on a common to the rolling stand 10, not shown here base plate and thus defined relative to the roll stand 10 is positioned ,

In the present case, the scraper unit 18 comprises two stripping devices 20, 21 arranged one above the other, aligned parallel to the axis direction of the rollers in the rolling stand 10. The stripping devices 20, 21, which in a front view in FIG Fig. 2 are each shown a scraper 22, 23 with a rectangular profile 48 which are arranged in the longitudinal direction of the stripping means 20, 21. Both scrapers 22, 23 are arranged at an angle α inclined to the strip running direction 15 in the stripping devices 20, 21, such that by one of four longitudinal edges of the scrapers 22, 23 a rolling surface 24 closest stripping edge 25 and 26 is formed.

As Fig. 1 Furthermore, the scrapers 22, 23 are each detachably connected to a base body 29, 30 of the respective scraper 22, 23 by means of a clamping strip 27, 28. Fig. 2 shows that in the present embodiment, the releasable connection of the terminal strips 27, 28 with the main bodies 29, 30 via screw 31 takes place. Each stripping device 20, 21 has a cleaning device 32, 33 which, like Fig. 1 shows, each formed in the main body 29, 30 nozzles 34 and a detergent supply line 35 which is connected to the main body 29, 30 and is connected via a cleaning agent channel 36 to the nozzle 34.

As Fig. 4 shows the nozzles 34 are arranged in the illustrated embodiment, that starting from a longitudinal direction of the Wiper 20, 21 center nozzle 34 to the axial ends of the stripping device 20, 21, the nozzles 34 are employed obliquely to the ends, wherein the nozzles 34 formed in use from cleaning fluid 47 spray cone 49.

As in particular from a synopsis of Fig. 1 and 3 As can be seen, the stripping devices 20, 21 are arranged in a scraper frame 37 and are connected to the scraper frame 37 via piston rods 38 of piston / cylinder units 39. To relieve the piston rods 38 from transverse forces, the stripping devices 20, 21 are mounted in support guides 50 in the scraper frame 37.

As Fig. 3 shows, the scraper frame 37 is received on pins 40 on side walls 41, 42 of the machine frame 19 in the direction of a longitudinal axis 43 of the scraper device 20, 21 longitudinally displaceably mounted in both directions. At the in Fig. 2 arranged on the right side cheek 41 is a Oszilierantrieb 44 which includes a drive motor 45 which acts on a not shown here eccentric linkage 46 on the Abstreiferrahmen 37, with the result that the Abstreiferrahmen 37 with the drive motor 45 with the running in Fig. 2 drawn Oszillierhub H in the direction of the longitudinal axis 43 moves back and forth.

Subsequently, the operation of the in the Fig. 1-3 illustrated Abstreiferaggregats 18 in conjunction with the upper support roller 16 exemplified.

In the Fig. 1 shown configuration shows the superimposed scraper devices 20, 21 in a rolling break, in which the scrapers 22, 23 with their scraping edges 25, 26 are spaced from the roll surface 24 of the support roller 16. In the rolling break no actual rolling takes place, so that during the rolling break no rolled strip 14 is conveyed through the nip 13 therethrough. In this rolling break, in which the rolling stand so quasi "empty" runs, can a cleaning of the scraping edges 25, 26 take place in that the scraping edges 25, 26 are moved by actuation of the piston / cylinder units 39 with construction of only slight contact pressure against the roll surface 24 and in this position the scraping edges 25, 26 through the nozzles 34th the cleaning means 32, 33 cleaning liquid 47 is sprayed onto the roll surface 24. The cleaning liquid 47 is transported by means of the rotating in the direction of rotation roller surface 24 against the voltage applied to the roll surface 24 Abstreifkanten 25, 26 and there on impurities, such as rolling abrasion, which are located on the scraping edge 25, 26 act. Alternative to the illustration in Fig. 1 it is also possible to align the nozzles 34 so that the cleaning liquid 47 does not act on the roll surface 24 of the support roller 16 via a drive, but rather directly on the scraping edges 25, 26 acts.

Below the scrapers 22, 23 is shown in FIG Fig. 1 a collecting channel 51 extending along the stripping means 20, 21, which decreases starting from the center of the roll toward the strip edges of the rolled strip 14, that is to say approximately in the shape of a roof ( Fig. 2 ), and serves to catch the coolant or lubricant dripping from the wipers 22, 23 and to dissipate laterally beyond the belt edges. This prevents dripping coolant or lubricant from getting onto the rolled strip 14. In addition, the collecting channel 51 serves to selectively remove the abrasion or the rolling flakes originating from the rolled strip 14 during the cleaning process.

During the rolling process, the scraping edges 25, 26 are moved against the roll surface 24 of the support roll 16 and are at a corresponding contact pressure against the roll surface 24 at. In this case, both the method of Abstreifkanten 25, 26 against the roller surface 24 as well as the formation or adjustment of the contact pressure via corresponding traversing or advancing movements of the piston / cylinder units 39. In a starting operation at the beginning of the rolling cycle, a relatively low contact pressure is initially generated by the piston / cylinder unit 39, which is steadily increased with increasing peripheral speed of the support roller 16. In stationary operation of the roll stand, the contact pressure remains substantially unchanged, and then finally at a deceleration of the roll stand, so with decreasing roller peripheral speed, a corresponding return movement of the piston / cylinder units 39 preferably proportional to the speed reduction, to be reduced.

In addition to the initially mentioned action on the roller surface 24 of the support roller 16 with cleaning fluid 47 during the rolling break, or in exceptional cases during the rolling operation, in addition to the rolling break, a mechanical cleaning of the scraping edges 25, 26 take place in that the scraping edges 25, 26 below comparatively low contact pressure against the roller surface 24 abut and at the same time acting on the Abstreiferrahmens 37 oscillating longitudinal oscillations by means of the Oszilierantriebs 44, such that the scraping edges 25, 26 are applied during the abutment against the rotating roller surface 24 with longitudinally directed to the roll axis vibrations. As a result, impurities located on the scraping edges 25, 26 can be removed from the scraping edges 25, 26 by correspondingly induced flexing movements of the scraping edges 25, 26 on the roll surface 24.

Claims (20)

Method for removing coolant and / or lubricant from rolls of a roll stand (10), in which a rolled strip (14) is conveyed through a roll gap (13) formed between work rolls (1, 12) in the strip running direction (15) an inlet side and / or an outlet side of the roll stand at least one stripping (20, 21) with a scraper edge (25, 26) with contact pressure against a roll surface (24) of a work roll or the work roll in the roll stand supportive support roller (16, 17) is present,
characterized,
that the contact pressure is changed depending on an operating parameter of the rolling process. Method according to claim 1,
characterized,
that the contact pressure is changed depending on the roller peripheral speed. Method according to claim 2,
characterized,
that as the roller peripheral speed is increased, the contact pressure is increased and the contact is reduced as the roller peripheral speed is reduced. Method according to claim 3,
characterized,
in that a constant change in the contact pressure takes place as a function of the roller circumferential speed. Method according to claim 3,
characterized,
in that a discontinuous, in particular graduated, change in the contact pressure takes place as a function of the roller circumferential speed. Method according to one of the preceding claims,
characterized,
that a material or shape parameter of the stripping device (20, 21) is used as further parameters when changing the contact pressure. Method according to one or more of the preceding claims,
characterized,
that a material or shape parameter of the roller cooperating with the stripping device (20, 21) is used as a further parameter in the change of the contact pressure. Method according to one or more of the preceding claims,
characterized,
that as another parameter in changing the contact pressure a parameter determined by the coolant / lubricant is used. Method according to one of the preceding claims,
characterized,
that the stripping device (20, 21) or the roller surface (24) opposite the stripping device is cleaned during a rolling break by means of a cleaning device (32, 33) associated with the stripping device. Method according to claim 9,
characterized,
that the stripping device (20, 21) or the roller surface (24) is acted upon by a cleaning medium during a rolling break by means of the cleaning device (32, 33). Method according to claim 9 or 10,
characterized,
in that the stripping device (20, 21) is subjected to vibrations during a rolling break in the longitudinal direction of the scraping edges (25, 26). Apparatus for removing coolant and / or lubricant from rolls of a roll stand (10), in which a rolled strip (14) is conveyed through a roll gap (13) formed between work rolls (11, 12) in the strip running direction (15), with at least a stripping device (20, 21) arranged on an inlet side and / or outlet side of the rolling stand with a stripping edge (25, 26) extending transversely to the strip running direction (15), a pressure device associated with the stripping device with at least one pressure means for applying a pressure force to the stripping device in that the scraping edge of the stripping device is in contact with a roller surface (24) of the work roll and / or one of the work rolls in the roll stand supporting the support roller (16, 17) is applied, characterized
that the pressure device is associated with a control / regulating device which acts on the pressure means in response to an operating parameter of the rolling process with a manipulated variable, such that the wiper edge rests against the roller surface with a defined contact pressure. Device according to claim 12,
characterized,
in that the stripping device (20, 21) is arranged on the rolling stand (10) in such a way that it cooperates with the upper and / or lower support roller (16, 17). Device according to claim 13,
characterized,
in that the rolling stand (10) has a stripping device (20, 21) associated with both the inlet side and the outlet side of the upper and / or lower support roller (16, 17). Device according to one of claims 12 to 14,
characterized,
in that the stripping device (20, 21) has at least one scraper (22, 23) which has a profile with a plurality of parallel longitudinal edges and is received in the stripping device at an angle α to the strip running direction (15), such that the scraper edge (25, 26) is formed by a longitudinal edge of the scraper. Device according to claims 15,
characterized,
that the scraper (22, 23) has a rectangular profile. Device according to claim 15 or 16,
characterized,
that the scraper (22, 23) are interchangeable in the stripping means (20, 21) is accommodated. Device according to one of claims 12 to 17,
characterized,
that the stripping device is provided (20, 21) with a cleaning device (32, 33). Device according to claim 18,
characterized,
in that the cleaning device (32, 3) has means for acting on the wiping edge (25, 26) or the roller surface (24) with a cleaning medium. Device according to claim 18 or 19,
characterized,
in that the stiffening device (20, 21) has a vibration generator for acting on the wipers (22, 23) with vibrations in the longitudinal direction of the wipers.

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