GB2072556A - Rolling and flattening strip - Google Patents
Rolling and flattening strip Download PDFInfo
- Publication number
- GB2072556A GB2072556A GB8010993A GB8010993A GB2072556A GB 2072556 A GB2072556 A GB 2072556A GB 8010993 A GB8010993 A GB 8010993A GB 8010993 A GB8010993 A GB 8010993A GB 2072556 A GB2072556 A GB 2072556A
- Authority
- GB
- United Kingdom
- Prior art keywords
- strip
- rolls
- bend
- mill
- rolling mill
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/28—Control of flatness or profile during rolling of strip, sheets or plates
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D1/00—Straightening, restoring form or removing local distortions of sheet metal or specific articles made therefrom; Stretching sheet metal combined with rolling
- B21D1/05—Stretching combined with rolling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B2275/00—Mill drive parameters
- B21B2275/02—Speed
- B21B2275/04—Roll speed
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B38/00—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product
- B21B38/06—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product for measuring tension or compression
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B39/00—Arrangements for moving, supporting, or positioning work, or controlling its movement, combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B39/02—Feeding or supporting work; Braking or tensioning arrangements, e.g. threading arrangements
- B21B39/08—Braking or tensioning arrangements
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Control Of Metal Rolling (AREA)
- Metal Rolling (AREA)
- Straightening Metal Sheet-Like Bodies (AREA)
Abstract
A method of improving strip shape during rolling involves introducing at least two intermediate bend rolls (12, 13) (Fig. 1) between adjacent mill stands (10, 11) and adjusting the speeds of the adjacent mill stands so that so as to stretch the strip during the bending. The strip (14) leaving the bend rolls may be made to travel 5% faster than the strip entering the bend rolls by adjustment of mill roll speeds. The method is applicable to both hot and cold rolling. <IMAGE>
Description
SPECIFICATION
Rolling and flattening strip
This invention relates to a method of improv
ing strip shape during rolling of metal strip.
Hot and cold mills are principally employed as a means for reducing strip thickness but this must be achieved in such a way that thickness variations across the width of the strip and along the length of the strip are small and it is particularly important that strip shape produced is good i.e. the strip must be flat and free from "wavy" edges or middles which are primarily a result of excessive reduction in thickness in region of the slack or "wavy" parts of the strip. Deflection of the
mill rolls and variations in roll diameter arising from unequal thermal expansion because of temperature gradients lead to bad shape.
An object of this present Invention is to provide means for correcting strip shape defects during the hot and cold rolling processes.
Stretch levelling over bend rolls is well known. The present Invention incorporates stretch levelling in a practicable way between the stands of a hot or cold mill.
A further object of this Invention is to achieve proper control of the mill stand speeds in relation to the stretch levelling operation.
In accordance with the present invention, there is a method of improving strip shape during rolling of metal strip in a rolling mill comprising introducing at least two intermediate bend rolls between adjacent mill stands of a rolling mill and adjusting the speeds of said adjacent mill stands so that the strip is made to stretch as it passes over the intermediate bend rolls.
Preferably the strip is arranged to pass over one of the bend rolls and under another bend roll.
Preferably the speeds of the adjacent mill stands are so arranged that the strip leaving the bend rolls travels faster than the strip entering the bend rolls, the increase being for example of the order of 5%.
At least one of the bend rolls may be mounted on means which provide a direct measurement of strip tension so that strip tension and therefore elongation can be measured and controlled, and said means may be, for example, a torque arm or a load cell.
The bending rolls may be undriven and have means for measuring accurately the speed of rotation of the bending rolls, the measured difference in the speed of the two bending rolls being used to control the relative speed of the adjacent entry and exit mill stands to maintain a predetermined speed difference between the two bending rolls so as to control strip elongation, the speed measuring means preferably being digital tachometers.
The method may be applied either to hot rolling of strip or to cold rolling of strip and particularly to steel strip.
From another aspect the invention lies in a strip rolling mill comprising, between two adjacent roll stands of the mill, a stretch leveller incorporating at least two bend rolls, and including means for adjusting the speeds of said adjacent mill stands so that the strip can be stretched as it passes over said bend rolls.
Preferably at least one of the bend rolls incorporates means, such as a torque arm or load cell, for measuring strip tension.
In the accompanying drawings: Figure 1 illustrates, diagrammatically, two adjacent mill stands of a hot rolling mill embodying the invention; and
Figure 2 illustrates a method in accordance with the invention of controlling the speeds of the bend rolls by controlling mill stand speeds.
In Fig. 1 is shown two adjacent hot mill stands 10 and 11 of conventional form. Interposed between mill stands 10 and 11 is a pair of pivoted bend rolls 12, 13 through which is treaded a steel strip 14 which is being rolled. Bend rolls 12 and 13 are supported on arms 15 and 16 which are pivoted on shafts 17, 18 respectively. Thus by swinging arm 15 anti-clockwise it may be moved from the firm line position to the dotted line position in contact with the strip 14. Similarly, roll 13 may be brought into the dotted line position by swinging arm 16 anticlockwise.
After the strip 14 has been threaded through the bend rolls 12 and 13 via guides 19 and 20 these bending rolls are brought into engagement with the strip so that the strip is partially warpped around them as shown in Fig. 1. The speeds of the mill stands are then adjusted so that strip is made to stretch as it passes over the intermediate bending rolls; speeds are adjusted so that strip leaving the bend rolls runs slightly faster (say 5% more) than the strip approaching the bend.roll. This stretching will remove shape defects from the strip. At the same time the effect of the bend rolls produces uniform stretching of the strip and prevents excessively high tensions from developing in the strip which otherwise cause local "necking" and even strip breakage.
The proper control of mill stand speeds in relation to the stretch levelling operation carried out by use of the bend rolls may be achieved in two ways.
(a) At least one of the bend rolls can be mounted on a torque arm or similar means or can be mounted directly onto a load cell so that a direct measurement of strip tension can be obtained. Strip tension is of course related to the elongation which would be obtained in passing over bending rolls of given diameter, and so we can control elongation at the bend rolls by controlling strip tension to a predetermined level.
(b) Fig. 2 shows the two bending rolls between the two mill stands of Fig. 1. These rolls are, in this instance, undriven and accurate digital tachometers T1 and T2 are mounted on the rolls to determine their speed of rotation which is of course a direct measure of strip speed at each roll. Difference in roll speed will be given as the difference in tachometer signals and this will be proportional to strip elongation. Thus, the tachometer signals are used to control the relative speed of the entry and exit mill stands in order to maintain a given speed difference between the two bend rolls.
Other forms of stretch levelling devices which could be used in place of the bend rolls are illustrated in our own earlier U.K. Patent
Specification Nos. 1122081, 1219966, 1219967, 1394083 and 1,545,114.
The bend rolls may be of small diameter (say, 7" or 8") compared with conventional
Looper rolls. If desired the bend rolls may be backed up by a series of staggered backing rolls or by two full-width backing rolls of conventional type.
Claims (18)
1. A method of improving strip shape during rolling of metal strip in a rolling mill comprising introducing at least two intermediate bend rolls between adjacent mill stands of a rolling mill and adjusting the speeds of said adjacent millstands so that the strip is made to stretch as it passes over the intermediate bend rolls.
2. A method according to claim 1 and in which the strip is arranged to pass over one of the bend rolls and under another bend roll.
3. A method according to claim 1 or claim 2 and in which the speeds of the adjacent mill stands are so arranged that the strip leaving the bend rolls travels faster than the strip entering the bend rolls.
4. A method according to claim 3 and in which the strip leaving the bend rolls is travelling at a speed of the order of 5% faster than the strip entering the bend rolls.
5. A method according to any preceeding claim and in which at least one of the bend rolls is mounted on means which provide a direct measurement of strip tension so that strip tension and therefore enlongation can be measured and controlled.
6. A method according to claim 5 and in which said means is either a torque arm or a load cell.
7. A method according to any of claims 1 to 4 and in which said bending rolls are undriven and have means for measuring accurately the speed of rotation of the bending rolls, the measured difference in the speed of the two bending rolls being used to control the relative speed of the adjacent entry and exit mill stands to maintain a predetermined speed difference between the two bending rolls so as to control strip elongation.
8. A method according to claim 7 and in which the speed measuring means are digital tachometers.
9. A method according to any preceedipg claim applied to a hot mill for hot rolling of strip.
10. A method according to any of claims 1 to 4 applied to a cold mill for cold rolling of strip.
10. A method according to any of claims 1 to 4 applied to a cold mill for cold rolling of strip.
11. A metal strip rolling mill comprising, between two adjacent roll stands of the mill, a stretch leveller incorporating at least two bend rolls, and including means for adjusting the speeds of said adjacent mill stands so that the strip can be stretched as it passes over said bend rolls.
12. A rolling mill according to claim 11 in which at least one of the bend rolls incorporates means for measuring strip tension.
13. A rolling mill according to claim 12 and in which said means for measuring strip tension comprises a torque arm or a load cell.
14. A rolling mill according to claim 11 and in which the bending rolls are undriven and incorporate means for accurately measuring the speed of rotation of the bending rolls.
15. A rolling mill according to claim 14 and in which said means is one or more digital tachometers.
16. A hot rolling mill according to any of claims 11 to 15.
17. A cold rolling mill according to any of claims 11 to 15.
18. A hot strip rolling mill substantially as hereinbefore particularly described and as illustrated in the accompanying drawings.
18. A method of improving strip shape during rolling of metal strip substantially as herein before particularly described and as illustrated in the accompanying drawings.
19. A strip rolling mill substantially as hereinbefore particularly described and as illustrated in the accompanying drawings.
CLAIMS (6 Oct 1980)
1. A method of improving strip shape during rolling of hot metal strip in a rolling mill comprising introducing at least two intermediate bending rolls between adjacent mill stands of a hot rolling mill and adjusting the speeds of said adjacent mill stands so that the strip is made to stretch as it passes over the intermediate bend rolls.
2. A method according to claim 1 and in which the strip is arranged to pass over one of the bend rolls and under another bend roll.
3. A method according to claim 1 or claim 2 and in which the speeds of the adjacent mill stands are so arranged that the strip leaving the bend rolls travels faster than the strip entering the bend rolls.
4. A method according to claim 3 and in which the strip leaving the bend rolls is travelling at a speed of the order of 5% faster than the strip entering the bend rolls.
5. A method according to any preceeding claim and in which at least one of the bend rolls is mounted on means which provide a direct measurement of strip tension so that strip tension and therefore elongation can be measured and controlled.
6. A method according to claim 5 and in which said means is either a torque arm or a load cell.
7. A method according to any of claims 1 to 4 and in which said bending rolls are undriven and have means for measuring accurately the speed of rotation of the bending rolls, the measured difference in the speed of the two bending rolls being used to control the relative speed of the adjacent entry and exit mill stands to maintain a predetermined speed difference between the two bending rolls so as to control strip elongation.
8. A method according to claim 7 and in which the speed measuring means are digital tachometers.
9. A method according to any preceeding claim and in which each bending roll is withdrawable from the strip path to facilitate feeding of the strip through the adjacent hot rolling mill stands.
10. A metal strip rolling mill comprising, between two adjacent roll stands of the mill, a stretch leveller incorporating at least two bend rolls, and including means for adjusting the speeds of said adjacent mill stands so that the strip can be stretched as it passes over said bend rolls.
11. A rolling mill according to claim 10 in which at least one of the bend rolls incorporates means for measuring strip tension.
12. A rolling mill according to claim 11 and in which said means for measuring strip tension comprises a torque arm or a load cell.
13. A rolling mill according to claim 10 and in which the bending rolls are undriven and incorporate means for accurately measuring the speed of rotation of the bending rolls.
14. A rolling mill according to claim 13 and in which said means is one or more digital tachometers.
15. A hot rolling mill according to any of claims 10 to 14.
16. A cold rolling mill according to any of claims 10 to 14.
17. A method of improving strip shape during hot rolling of metal strip substantially as hereinbefore particularly described and as illustrated in the accompanying drawings.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8010993A GB2072556A (en) | 1980-04-02 | 1980-04-02 | Rolling and flattening strip |
| JP4569981A JPS56154211A (en) | 1980-04-02 | 1981-03-30 | Method of improving shape of strip |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8010993A GB2072556A (en) | 1980-04-02 | 1980-04-02 | Rolling and flattening strip |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2072556A true GB2072556A (en) | 1981-10-07 |
Family
ID=10512548
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8010993A Withdrawn GB2072556A (en) | 1980-04-02 | 1980-04-02 | Rolling and flattening strip |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS56154211A (en) |
| GB (1) | GB2072556A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2309185A (en) * | 1996-01-16 | 1997-07-23 | Draftex Ind Ltd | Stress relief of metal strip |
| EP1289685A1 (en) * | 2000-05-26 | 2003-03-12 | Castrip, LLC | Hot rolling thin strip |
| DE102015101580B3 (en) * | 2015-02-04 | 2016-06-02 | Hydro Aluminium Rolled Products Gmbh | Method and device for embossing a strip |
| CN111604697A (en) * | 2020-05-31 | 2020-09-01 | 日照宝华新材料有限公司 | Control method for transverse folding defect of thin-specification low-carbon steel |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2518370B2 (en) * | 1988-12-28 | 1996-07-24 | 株式会社安川電機 | Tension leveler control method |
-
1980
- 1980-04-02 GB GB8010993A patent/GB2072556A/en not_active Withdrawn
-
1981
- 1981-03-30 JP JP4569981A patent/JPS56154211A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2309185A (en) * | 1996-01-16 | 1997-07-23 | Draftex Ind Ltd | Stress relief of metal strip |
| EP1289685A1 (en) * | 2000-05-26 | 2003-03-12 | Castrip, LLC | Hot rolling thin strip |
| EP1289685A4 (en) * | 2000-05-26 | 2006-05-31 | Castrip Llc | Hot rolling thin strip |
| US7093342B2 (en) | 2000-05-26 | 2006-08-22 | Castrip Llc | Hot rolling thin strip |
| DE102015101580B3 (en) * | 2015-02-04 | 2016-06-02 | Hydro Aluminium Rolled Products Gmbh | Method and device for embossing a strip |
| US10751773B2 (en) | 2015-02-04 | 2020-08-25 | Hydro Aluminium Rolled Products Gmbh | Method and apparatus for roll-embossing a strip |
| CN111604697A (en) * | 2020-05-31 | 2020-09-01 | 日照宝华新材料有限公司 | Control method for transverse folding defect of thin-specification low-carbon steel |
| CN111604697B (en) * | 2020-05-31 | 2021-05-14 | 日照宝华新材料有限公司 | Control method for transverse folding defect of thin-specification low-carbon steel |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS56154211A (en) | 1981-11-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |