EP1399277A1

EP1399277A1 - Method and device for cooling and lubricating rollers on a rolling stand

Info

Publication number: EP1399277A1
Application number: EP02754755A
Authority: EP
Inventors: Jürgen Seidel
Original assignee: SMS Demag AG
Current assignee: SMS Siemag AG
Priority date: 2001-06-28
Filing date: 2002-06-25
Publication date: 2004-03-24
Anticipated expiration: 2022-06-25
Also published as: CA2452057C; US7159433B2; DE50203972D1; CN1240494C; US20040217184A1; CA2452057A1; ES2247363T3; RU2287386C2; MXPA03011355A; TWI259111B; ATE302072T1; BR0209701A; JP2004532130A; EP1399277B1; WO2003002277A1; CZ20033076A3; BR0209701B1; AU2002321114B2; DE10131369A1; CN1537035A

Abstract

The invention relates to a method and a device for cooling and/or lubricating rollers, in particular the working rollers ( 2, 3 ) on a rolling stand and a rolled strip ( 1 ), rolled between the above rollers and transported onwards, using water in the form of spray jets ( 4, 5 ) as cooling medium and oil, oil/water mix, oil/water mix, oil/air/water mix or grease mixtures as lubricant. In order to improve the lubricating and cooling effects, a combined application of super-cooling the strip and roller surfaces and roller lubrication on the input side of the stand is disclosed, in which both media, water and lubricant, are separately fed to the rollers ( 2, 3 ) and the rolled strip and applied to the roller surface at different application points. Separate reservoirs for water and lubricant and separate lines to the spraying bar ( 11 ) for water and the spraying bar ( 12 ) for the lubricant are provided.

Description

Method and device for cooling and lubricating rolls of a roll stand

The invention relates to a method for cooling and / or lubricating rolls, in particular work rolls of a roll stand and a rolled strip conveyed between them during rolling.

In particular when thin slab rolling to small final thicknesses, a high pass reduction in the individual roll stands is required. This results in an extraordinarily high mechanical, but also thermal load on the rolls, especially the work rolls. As a result, the surface of the rollers in the front stands, in particular, deteriorates with an increasing number of strips. This manifests itself in the form of rolls becoming rougher and even in the "peeling" of the rolls, with the oxide layer becoming detached from the roll in places. The resulting irregular roller roughness ultimately leads to the rolling of scale into the strip surface, which also adversely changes the quality of the strip surface.

With extremely high stitch decreases, vibrations of the work rolls, i.e. torsional vibrations of the two work rolls occur against each other.

With the help of good roll cooling on the strip inlet and outlet side of the stand, the roll temperature and thus the geometric expansion of the rolls can be limited, but it cannot prevent the high thermal loads in the roll gap and thus the aforementioned difficulties.

In the prior art, document DE 41 34 599 C1 shows a measure against the high thermal load in the roll gap by subcooling the strip surface and roll surface shortly before the roll gap. This results in a lower heat flow into the roller when the surface layers of the rollers and the rolled strip are supercooled. However, in order to achieve a sufficient cooling effect with this method, a relatively large amount of water is required, although the effect is not sufficient with large reductions in thickness.

Another method of avoiding or reducing the roll peeling and rolling of scale, according to a procedure described in document EP 09 08 248 A2, is to lubricate the rolls.

One method of application, which has also become established, is still to spray the rolls with an oil / water mixture in front of the roll gap. A small amount of water serves as a carrier medium for the oil. The addition of lubricant is intended to reduce the coefficient of friction and in some cases to create a thin oil separating layer that protects the roller against wear.

For economic reasons and for reasons of environmental protection, an admixture of oil to produce an oil-water mixture, for example in the chilled beam according to document DE 41 34 599, when using a large amount of water is undesirable. This also has the further reason that with a large amount of water a correspondingly large amount of oil would also be required so that the mixing ratio remains optimal and a lubricating effect is achieved. For this reason, a separate small lubrication bar with a small amount of water is often used as a carrier medium for applying the oil.

However, even with this method, the result is in no way satisfactory with high stitch declines in terms of roller peeling and roller roughness. Only a significant damping of the vibration is found.

Another area of technology is for the lubrication and cooling of workpieces in machining processes according to the document It is known from EP 0 69 07 66 to supply the workpieces with at least two immiscible fluids, namely a substrate for reducing the friction between the cutting edge and the workpiece, and a substrate for cooling the cutting edge and the workpiece, the two substrates being stored separately from one another via separate feed lines conveyed to an application organ and sprayed from it onto the workpiece to be machined.

To this end, the description states that the method and the device achieve a substantial increase in the lubricating and cooling effect and that the means and expenditure required for this in terms of material, energy and equipment are kept within the narrowest possible economic limits.

Furthermore, it is said that the application of lubricant and coolant at separate locations on the tool and the resulting lubricant film of extremely high adhesion and shear strength results in a significantly improved lubricating effect and, as a result, reduced friction on the workpiece, tool and chips with less frictional heat, which means that As a result of the more favorable cooling conditions, the quality of the machined surfaces is improved, the energy requirement of the machine is reduced and the tool life is increased.

A largely similar method for the lubrication and cooling of cutting edges or workpieces is also known from DE 43 09 134 A1, according to which when the cutting edge and workpiece move relative to the machining area, first the lubricant and only then the coolant in accordance with the required cooling of Workpiece and tool is sprayed on. For this purpose, the temperature of a cutting edge or a tool or a workpiece is determined and the feed rate of one of the two fluids is set in accordance with the determined temperature.

Starting from the aforementioned prior art, the object of the present invention is to provide the roll cooling and roll lubrication to improve a heavily loaded roll stand and to use lubricants more economically.

To achieve this object, the invention provides for the use of water in the form of spray jets as a coolant in a method of the type mentioned in the preamble of claim 1 for cooling and lubricating rolls, in particular the work rolls of a roll stand and a rolled strip conveyed between them during rolling. as well as oil, oil-air mixture, oil-water mixture or oil-water-air mixture as a lubricant, the media - water or lubricant - being fed separately to the rollers or the rolling belt and being scrapped at different application points. side of the roller surface or the surface of the rolled strip are applied. Fat or a mixture of fat and medium can be used instead of oil.

It is a great advantage that this results in optimal use of the lubrication or cooling effect of the two media, water and lubricant, and thus a reduction in power and labor requirements, due to minimized friction coefficients on the rollers. The ground surface of the roller can withstand even the highest demands. The material peeling on the rollers observed so far is prevented. The surface of the rolled strip remains optimally smooth. Scale inclusions and chatter marks on the belt surface are eliminated.

In an embodiment of the invention it is provided that the lubricant is applied in the form of an oil, oil-air mixture or oil-water mixture, or oil-water-air mixture in order to achieve the most adhesive film possible on largely water-free areas of the roller surface. This ensures a good spreading of the oil film on the roller surface, so that the oil film adheres well and cannot be easily washed off by spray water later on and maintains its full lubricating effect. The same effects are also achieved when using grease as a lubricant component for a grease-medium mixture. To further develop the method according to the invention, it is proposed that the application areas for applying the cooling medium and the lubricant be separated from one another by means of wipers. Advantageously, the so-called wipers, which are present anyway, are used to separate the application sites for water and lubricant in the simplest way. The cooling water of the work roll cooling on the outlet side is shielded by the backup roll.

Furthermore, depending on the boundary conditions and the resulting requirements, it is provided that either only the lubricant is applied at this favorable point of application, or that only the cooling of the strip is activated.

In a further development of the invention, it is proposed that water jets are applied on the inlet side in front of the roll gap on the upper and / or lower side of the strip, the water jets preferably being directed against the strip, and that lubricant is applied to an area at the top and bottom the rollers - seen in the direction of rotation - takes place on the inlet side in front of the areas of water application. According to the invention, there is therefore a direct application of water in front of the roll gap on the upper and / or lower side of the strip, the water jets being primarily aimed at the strip in order not to wash away the previously applied lubricating oil. Nevertheless, the orientation of the water jets indirectly results in additional cooling of the roller surface.

In order to optimize the combined use of cooling of the strip and roller surface and roller lubrication, according to a further proposal of the invention, the inlet-side roller cooling is deactivated in the case of active lubrication, the excess water from the inlet side being used to intensify the outlet-side roller cooling. The further intensive cooling of the rollers on the outlet side takes place exclusively with water spray. If the lubrication is not active, the roller cooling is activated on the inlet side.

In a variant of the invention, use can also be made of the measure that the strip is exposed to water jets on the inlet side and as close as possible in front of the roll gap with a jet direction against the strip running direction, the separation of the points of exposure for water also in this case and lubricants must be provided.

A device for cooling and / or lubricating rolls according to the invention, in particular the work rolls of a roll stand and a rolled strip rolled and conveyed between them, using water in the form of spray jets as the cooling medium and a lubricant, provides that the media - water and lubricant - in each case separate storage containers and separate feeds to pressurizing elements for water and to pressurizing elements for lubricants are assigned.

In order to separate the application sites of the two spray bars for water and lubricant from one another, it is proposed in one embodiment of the device that the arrangement of a lubricant spraying device is provided on the upper roller above a scraper and on the lower roller below a scraper, which is more advantageous Way can be used on the wipers already present in roll stands.

To further develop the device according to the invention, a deflection plate or water spreading plate directed against the rolled strip or water spreading plate for the spray jets can be used below the upper inlet-side scraper and above the lower inlet-side scraper in order to distribute the spray water on the rolled belt as evenly as possible and without streaking. This can be a sheet on each side, but also two baffles that focus the water jet in a funnel shape in order to achieve the best possible uniformity of the coolant jet across the width of the rolling surface.

Alternatively, a so-called water curtain can be used for cooling the tape, for example according to DE patent 28 04 982, the water emerging from a rectangular slot and being sprayed against the tape. Here, an optimization of the water curtain provides that the opening width of the outlet slot is adjustable in order to accommodate e.g. B. to realize cleaning purposes or variable amounts of water as favorable conditions as possible.

Applying the lubricant above the upper or below the lower scraper makes it possible to collect the lubricant again after the application.

This results in a further inventive embodiment of the application of lubricant, the lubricant sprayed onto the roller being limited in a shielding shell and diverted to the rear or to the side, so that the lubricant is removed or processed or disposed of separately from the other cooling media, is made possible.

Details, features and advantages of the invention result from the following explanation of an exemplary embodiment shown schematically in the drawings:

Figure 1 shows a side view of the roll cooling and roll lubrication device with schematically indicated spray jets of water and lubricant.

Figure 2 shows a further arrangement of nozzles for strip cooling immediately before the roll gap when using a water curtain. Figure 3 shows an alternative arrangement of baffles and shielding shells for separate removal of the lubricant.

According to FIG. 1, a roll strip 1 between the work rolls 2, 3 of a roll stand (not shown in detail) is reduced in thickness by approximately 50% in a single pass. The following stands, also not shown in more detail, have approximately the same large stitch decreases. In order to limit the high mechanical but also the high thermal load and not to deteriorate the roll surfaces even with an increasing number of strips, a combined use of cooling of the strip and lubrication of the roll surface is carried out with the following measures.

In the case of the cooling and lubricating device shown, the media - water or lubricant - are separate storage containers (not shown in each case) and separate feeds to the pressurizing elements 11, 11 '; 11 "for water 4.5 and assigned to the separate application members 12, 12 'for lubricants 10, 10'. In general, these application members are designed as lubrication and cooling bars. The arrangement of the lubricant bars 12 on the upper work roll 3 is above a scraper 9. The arrangement of the lubricant bar 12 'is provided on the lower work roll 2 below the scraper 8. The upper water cooling bar 11 for cooling the upper side of the strip 1 is below the scraper 9 and the lower water cooling bar 11 for cooling the lower side of the rolled strip 1 is arranged above the scraper 8. With the help of the water cooling beams 11, water spray jets 4, 5 are directed onto the roll strip surfaces in front of the roll gap of the work rolls 2, 3. With the aid of the deflection plate 14 above the roll strip 1 and with the aid of the deflection plates 13 below the roll strip 1 the water spray jets 4, 5 are deflected so that they are possible ht directly in the inlet-side area of the roll gap and there in the application areas 7, 7 'for immediate cooling of the roll des 1 and for indirect cooling of the work rolls 2, 3 achieve the optimal effect.

An alternative arrangement of the deflection plates can also be seen in FIG. 3. Here, a water jet is focused in a funnel shape by means of two baffle plates in order to achieve the best possible uniformity of the jet across the roll width.

The lubrication bars 12, 12 'are provided for generating lubricant spray jets 10, 10'. The lubricant is applied to the largely water-free area of the roll surface of the work rolls to achieve the most adhesive film possible. The spray oil 10, 10 '- seen in the direction of the rotation of the rollers - is applied at a point close to the wipers 8, 9.

For further intensive cooling of the work rolls 2, 3, further water cooling beams 11 'are arranged on the outlet side of the work rolls, from which only water spray jets 4, 5 are directed against the roll surfaces. The cooling water of the work roll cooling 11 ′ on the outlet side is shielded by the support rolls 15, 15 ′, so that the areas 6, 6 ′ remain dry

The lubrication and cooling beams 11, 12 can be controlled so that the inlet-side water cooling 11 "is deactivated in the case of active lubrication and the roller cooling 11" is activated when the lubrication is not active. If the roller cooling 11 "on the inlet side is deactivated, excess water is fed from there to intensify the roller cooling on the outlet side, that is to say the cooling bars 11 'arranged there. It is also possible to switch from the combined roller cooling and roller lubrication with separate loading locations to one exclusive water cooling, with all the water cooling bars 11, 11 '; 11 "shown being activated and the lubricating bars 12 being deactivated as a whole. A further embodiment of the arrangement is shown in FIG. 2 for strip cooling immediately before the roll gap. Here water 4, 5 emerges from a rectangular slot and is sprayed against the belt 1. With an eccentric adjustment 19, which can be operated manually or by a motor, the slot or opening width can be continuously adjusted by rotating the shaft.

An embodiment of the lubricant supply according to FIG. 3 further provides that lubricant 10, 10 'sprayed onto the work roll is passed past and returned to the roll within a shielding shell 16, 16'. The pivotable shielding shell shows a feed line 17, 17 'for the lubricant 10, 10' and a discharge line 18, 18 '.

Depending on the version, the lubricant can also be drained off to the side and then collected. This means that the lubricant can be processed or disposed of if necessary. This prevents it from accumulating in the cooling circuit.

The arrangement of lubricating and cooling bars for lubricants and water spray jets shown in FIGS. 1 to 3 and the method for cooling and lubricating the work rolls of a rolling stand realized with the new arrangement is not only limited to the exemplary embodiment shown, but also includes other variants if they satisfy the invention.

List of reference numbers

1 rolled strip

2 work roll below

3 work roll on top 4 water spray on top

5 water spray below

6 Lubricant application area

7 Water exposure area

8 wipers below 9 wipers above

10 lubricants

11 Water act

12 Lubricant loading device

13 bottom baffle 14 top baffle

15 backup roller

16 shielding shell

17 supply line

18 discharge line 19 eccentric adjustment

Claims

claims

1. A method for cooling and / or lubricating rolls, in particular work rolls (2, 3) of a roll stand and a rolled strip (1) rolled and conveyed between them, characterized by

Use of water in the form of spray jets (4, 5) as a cooling medium and oil, oil-air mixture, oil-water mixture, or oil-water-air mixture or also grease or grease-medium mixture as a lubricant, the two media - water or lubricant - being fed separately to the rolls or the rolled strip and being applied to the roller inlet or the rolled strip surface on the scaffold inlet side at different application points.

2. The method according to claim 1, characterized in that the lubricant in the form of oil, oil-air mixture, oil-water mixture, or oil-water-air mixture, or fat or fat-media mixture for Achieving the most adhesive film possible is applied to largely water-free areas of the roller surface.

3. The method according to claim 1 or 2, characterized in that the application areas (6, 7; 6 ', 7') for applying the two media water or lubricant are separated from one another by means of scrapers (8, 9).

4. The method according to one or more of claims 1 to 3, characterized in that that depending on the boundary conditions and requirements either only one

Lubricant applied, or only the rolling belt cooling is activated.

5. The method according to one or more of claims 1 to 4, characterized in that an application (7, 7 ') with water jets (4, 5) takes place on the inlet side in front of the roll gap on the upper and / or lower side of the strip, the water jets (4, 5) are preferably directed against the belt (1), and that the application of lubricant (10, 10 ') at the top and bottom of each area (6, 6') of the rollers (2, 3) - in rotati - Seen ons direction - on the inlet side in front of the areas of water application (7, 7 ').

6. The method according to one or more of claims 1 to 5, characterized in that a further intensive cooling of the rollers (2, 3) on the stand outlet side is carried out exclusively with water spray jets (4, 5).

7. The method according to one or more of claims 1 to 6, characterized in that the lubricant (10) - seen in the direction of the roller rotation - at a point close to the wipers (8, 9) on the rollers and the cooling medium (4, 5) is applied to the roll belt as directly as possible before the roll gap.

8. The method according to one or more of claims 1 to 7, characterized in that the water spray jets (4, 5) with a baffle plate or water spreading plate in each case up and down against the strip for the most uniform possible application of water to the rolled strip (1) 1) be distracted.

9. The method according to one or more of claims 1 to 8, characterized in that a water curtain is used to cool the rolled strip, which emerges from a rectangular spray nozzle mouth and is directed against the strip.

10. The method according to one or more of claims 1 to 9, characterized in that the spray nozzle mouth has an adjustable opening width for a further embodiment of the water curtain.

11. The method according to one or more of claims 1 to 10, characterized in that the strip is acted upon with water jets (4, 5) on the inlet side and as close as possible in front of the roll gap with a jet direction against the strip running direction.

12. Method for controlling the cooling and / or lubrication of rolls (2, 3) of a roll stand and a roll strip (1) rolled and conveyed between them, using water spray jets (4, 5) as cooling medium and a lubricant ( 10, 10 '), characterized in that the inlet-side roller cooling (11 ") is deactivated in the case of active lubrication, and the roller cooling (11") is activated in the case of inactive lubrication, and that when the roller cooling on the inlet side is deactivated excess water from is used there to intensify the roll cooling on the outlet side.

13. Device for cooling and / or lubricating rolls, in particular work rolls (2, 3) of a roll stand and a rolled strip (1) rolled and conveyed between them, using water in the form of spray jets (4, 5) as cooling medium , and Lubricant (10, 10 '), in particular for carrying out the method according to claims 1 to 12, characterized in that the media - water or lubricant - in each case separate storage containers, as well as separate feeds to loading elements (11, 11', 11 " ) for water (4, 5), and to act as an actuator (12) for

Lubricants (10, 10 ') are assigned.

14. The apparatus according to claim 13, characterized in that the arrangement of a lubricant spray member (12) on the upper roller (3) above a wiper (9), and on the lower roller (2) below a wiper (8) is provided.

15. Device according to one of claims 13 or 14, characterized in that below the upper, inlet-side scraper (9), and above the lower inlet-side scraper (8) each have a deflecting plate (13, 14) or directed against the rolled strip (1) Water spreading sheet for the water spray lamps (4, 5) is arranged.

16. The apparatus according to claim 15, characterized in that two deflection plates (13, 14) are provided which focus the coolant jet (4, 5) in a funnel shape, such that the uniformity of the coolant jet across the width of the rolled strip (1) is further improved.

17. The device according to one or more of claims 13 to 16, characterized in that lubricant (10, 10 ') sprayed onto the roller is delimited in a shielding shell (16, 16') and sealed off to the rear or to the side. is passed, and that a discharge line (18, 18 ') for the preparation or disposal of lubricant is provided separately from other cooling media.