EP0471777A1 - Method for levelling thin strips by stretching and bending. - Google Patents

Method for levelling thin strips by stretching and bending.

Info

Publication number
EP0471777A1
EP0471777A1 EP90908320A EP90908320A EP0471777A1 EP 0471777 A1 EP0471777 A1 EP 0471777A1 EP 90908320 A EP90908320 A EP 90908320A EP 90908320 A EP90908320 A EP 90908320A EP 0471777 A1 EP0471777 A1 EP 0471777A1
Authority
EP
European Patent Office
Prior art keywords
levelling
line
strip
abscissa
rolls
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.)
Granted
Application number
EP90908320A
Other languages
German (de)
French (fr)
Other versions
EP0471777B1 (en
Inventor
Lars Ingvar Ingvarsson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Coil Processing Systems CPS Teknik AB
Original Assignee
Coil Processing Systems CPS Teknik AB
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Coil Processing Systems CPS Teknik AB filed Critical Coil Processing Systems CPS Teknik AB
Publication of EP0471777A1 publication Critical patent/EP0471777A1/en
Application granted granted Critical
Publication of EP0471777B1 publication Critical patent/EP0471777B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • 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

Definitions

  • the present invention concerns a method for levelling strips, the thickness of which is maximum 4 mm, by simultaneous stretching and bending and by help of two levelling rolls only.
  • Known levelling devices, fig 1 for levelling strips with a small thickness and widths, which can be considerable, is constituted in its central part of a number of zigzag-placed rolls 1 between which the strip 2 is passing and where the surface of the strip 2 is bended in two opposite directions.
  • the strip 2 is subjected to a stretching in order to move the elastic zone from the centre of the strip at the bendjng around the levelling rolls 1.
  • the main principle for the levelling of the strip 2 is to bring the material to exceed the yield point ⁇ s across the whole of its cross section in such a way that partly eventual buckles and others are removed, partly the strip leaving the last levelling roll without beeing bent.
  • the strip is passing the levelling device, fig 1, under a pull effected by a tractive force of the coiling reel 3 and the braking force of the decoiling reel 4.
  • Breaking rolls 5 are arranged on both sides of the levelling roll assembly to compensate changes in the pulling force in the strip 2 at changing outer diameters of the coils at coiling and decoiling. To get a good result a constant pull is required in the strip 2.
  • the stretching force in the strip usually is adjusted in that way that a specific pulling force of 20-40 % of the yield point is reached in the strip.
  • the diameter of the levelling rolls usually is dimensioned according to the unlevelty of the strip before levelling and the thickness of the strip.
  • roller diameter is about 100 times the thickness t of the strip, but can of course vary within wide limits.
  • a varying roller diameter in the assembly of levelling rolls also can be found.
  • the drawbacks of conventional roller levelling assemblies is among others that these, because of a great number of levelling rolls, are complicated to adjust to get level strips and rather expensive in manufacturing. Also the plastic area of the strip is utilised into a too high degree because of a great number of bendings, which reduces the area of finishing of the material before reaching the breaking point and also hardens considerably because of the cold working.
  • a radius R1 of the first levelling roll 1 is choosen, which because of earlier experiances from roller levelling devices shall be around or somewhat below 50 times the thickness t of the strip 2.
  • a distance a is pointed out from the origin of coordinates along the abscissa, which distance is equal to the thickness t of the strip divided by the radius R1 of the first roll, and from that point a first parallel line 10 is drawn up against the plasticity line 9, parallel to the elasticity line 7.
  • a first surface 11 is constituted in the diagram, fig 2, between the abscissa, the elasticity line 7, the first parallel line 10 and the plasticity line 9.
  • a new second parallel line 12 is drawn to the right of the first surface 11 in that way that a second surface 13 between the abscissa, the first and the second parallel line 10, 12 and the plastcity line 9 becomes equal to the first surface 11.
  • the distance b along the abscissa between the first and the second parallel line 10, 12 is measured.
  • the thickness t of the strip 2 is devided with the later distance b which constitutes the radius R2 of the second levelling roll 1 in the rollsr levelling device, fig 1.

Landscapes

  • Mechanical Engineering (AREA)
  • Engineering & Computer Science (AREA)
  • Straightening Metal Sheet-Like Bodies (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
  • Treatment Of Fiber Materials (AREA)
  • Stringed Musical Instruments (AREA)
  • Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
  • Decoration Of Textiles (AREA)
  • Luminescent Compositions (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Bending Of Plates, Rods, And Pipes (AREA)
  • Shaping Of Tube Ends By Bending Or Straightening (AREA)

Abstract

The invention describes a method for roller levelling of strips with a maximum thickness of 4 mm by simultaneous stretching and bending by passing the strip (2) through a conventional roller levelling device with only two levelling rolls (1) but with a certain relation between the radiuses of the levelling rolls depending of the characteristics and thickness of the material in the strip (2).

Description

TITLE
Method for levelling thin strips by stretching and bending.
FIELD
The present invention concerns a method for levelling strips, the thickness of which is maximum 4 mm, by simultaneous stretching and bending and by help of two levelling rolls only.
BACKGROUND TECHNICS
Known levelling devices, fig 1, for levelling strips with a small thickness and widths, which can be considerable, is constituted in its central part of a number of zigzag-placed rolls 1 between which the strip 2 is passing and where the surface of the strip 2 is bended in two opposite directions. On the same time the strip 2 is subjected to a stretching in order to move the elastic zone from the centre of the strip at the bendjng around the levelling rolls 1. The main principle for the levelling of the strip 2 is to bring the material to exceed the yield point δs across the whole of its cross section in such a way that partly eventual buckles and others are removed, partly the strip leaving the last levelling roll without beeing bent. Thus the strip is passing the levelling device, fig 1, under a pull effected by a tractive force of the coiling reel 3 and the braking force of the decoiling reel 4. Breaking rolls 5 are arranged on both sides of the levelling roll assembly to compensate changes in the pulling force in the strip 2 at changing outer diameters of the coils at coiling and decoiling. To get a good result a constant pull is required in the strip 2. The stretching force in the strip usually is adjusted in that way that a specific pulling force of 20-40 % of the yield point is reached in the strip. The diameter of the levelling rolls usually is dimensioned according to the unlevelty of the strip before levelling and the thickness of the strip. Normally the roller diameter is about 100 times the thickness t of the strip, but can of course vary within wide limits. A varying roller diameter in the assembly of levelling rolls also can be found. The drawbacks of conventional roller levelling assemblies is among others that these, because of a great number of levelling rolls, are complicated to adjust to get level strips and rather expensive in manufacturing. Also the plastic area of the strip is utilised into a too high degree because of a great number of bendings, which reduces the area of finishing of the material before reaching the breaking point and also hardens considerably because of the cold working.
THE INVENTION
Surprisingly it has been found that strips can be levelled by only two levelling rolls if, besides of an appropiate pull in the strip and an appropiate dimension of the diameter of the breaking rolls, the mutual relation between the roller diameters is adjusted. The invention will be described in the claims enclosed, in the closer description below and by help of the enclosed drawings on which figure 1 schematically shows an ordinary straightening machine and figure 2 a tensile test diagram of the actual strip material.
CLOSER DESCRIPTION OF THE INVENTION
Initially pieces for tensile test are taken from the strip 2, which is to be levelled, tensile test is made and a diagram for stress and elongation is drawn up in a conventional way with the elongation ε as abscissa and the stress δ as ordinate, fig 2, (see the Swedish general specification SS 11 21 10). A mainly straight upward slooping line extends from the origin of the coordinates, the elasticity line 7, up to the yield point 8, which after that turns into a more level line, the plasticity line 9. The later line 9 whithout disadvantages can be approximated by a straight line. A radius R1 of the first levelling roll 1 is choosen, which because of earlier experiances from roller levelling devices shall be around or somewhat below 50 times the thickness t of the strip 2. A distance a is pointed out from the origin of coordinates along the abscissa, which distance is equal to the thickness t of the strip divided by the radius R1 of the first roll, and from that point a first parallel line 10 is drawn up against the plasticity line 9, parallel to the elasticity line 7. By that a first surface 11 is constituted in the diagram, fig 2, between the abscissa, the elasticity line 7, the first parallel line 10 and the plasticity line 9. A new second parallel line 12 is drawn to the right of the first surface 11 in that way that a second surface 13 between the abscissa, the first and the second parallel line 10, 12 and the plastcity line 9 becomes equal to the first surface 11. The distance b along the abscissa between the first and the second parallel line 10, 12 is measured. The thickness t of the strip 2 is devided with the later distance b which constitutes the radius R2 of the second levelling roll 1 in the rollsr levelling device, fig 1. These two rolls are used in a roller levelling device, fig 1, mentioned in the preamble, and the strip 2 is levelled in a usual manner by help of an appropriate pull. By that a level strip 2 is reached.

Claims

A method for levelling a thin strip (2) by stretching and bending in a roller levelling device (fig 1) constituted by a braked decoiling reel (4), a stress control device (5), unpowered rolls (1) and a powered coiling reel (3), c h a r a c t e r i z e d in that only two levelling rolls (1) are used and that the relation between their radiuses, R1 and R2, is determined by making a tensile test according to the Swedish general specification SS 11 21 10 of the material in the strip (2), a stress elongation diagram (fig 2) is drawn up with the elongation ε as abscissa and the stress d as ordinate, constituted by an elasticity line (7) starting from the origin of coordinates, followed by a plasticity line (9), that a distance a is set out from the origin of coordinates along the abscissa, which is equal to the thickness t of the strip (2) devided by the radius R1 of the first roll (1), and a first parallel line (10) is drawn parallel to the elasticity line (7) up to the plasticity line (9), that a second parallel line (12) is drawn in a corresponding way on a distance b along the abscissa from the first parallel line (10) in that way that the two surfaces (11, 13) constituted between the abscissa and the plasticity line (9) are equal and the radius R2 of the second levelling roll is determined according to the formula
EP90908320A 1989-05-11 1990-05-09 Method for levelling thin strips by stretching and bending Expired - Lifetime EP0471777B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8901686A SE463605B (en) 1989-05-11 1989-05-11 SETTING TO PLANGE THINNY SHEET TAPES MEDIUM STRAIGHT AND BENDING
SE8901686 1989-05-11

Publications (2)

Publication Number Publication Date
EP0471777A1 true EP0471777A1 (en) 1992-02-26
EP0471777B1 EP0471777B1 (en) 1993-09-08

Family

ID=20375919

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90908320A Expired - Lifetime EP0471777B1 (en) 1989-05-11 1990-05-09 Method for levelling thin strips by stretching and bending

Country Status (8)

Country Link
EP (1) EP0471777B1 (en)
AT (1) ATE94094T1 (en)
DE (1) DE69003242T2 (en)
DK (1) DK0471777T3 (en)
FI (1) FI915311A0 (en)
NO (1) NO176046C (en)
SE (1) SE463605B (en)
WO (1) WO1990013372A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2511611A1 (en) 2003-03-07 2012-10-17 Shikoku Research Institute Incorporated Hydrogen flame monitoring method and system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3590288B2 (en) * 1999-02-15 2004-11-17 住友重機械工業株式会社 Strip plate leveling method and leveling device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9013372A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2511611A1 (en) 2003-03-07 2012-10-17 Shikoku Research Institute Incorporated Hydrogen flame monitoring method and system

Also Published As

Publication number Publication date
NO914335L (en) 1991-11-05
NO176046C (en) 1995-01-25
DE69003242T2 (en) 1994-01-27
DE69003242D1 (en) 1993-10-14
NO914335D0 (en) 1991-11-05
NO176046B (en) 1994-10-17
WO1990013372A1 (en) 1990-11-15
FI915311A0 (en) 1991-11-11
SE463605B (en) 1990-12-17
ATE94094T1 (en) 1993-09-15
EP0471777B1 (en) 1993-09-08
SE8901686D0 (en) 1989-05-11
DK0471777T3 (en) 1994-03-14
SE8901686L (en) 1990-11-12

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