Flatness measuring and measuring of residual stresses for a metallic flat product

Patent metadata

Field	Value
Publication number	US-10081041-B2
Application number	US-201314651411-A
Country	US
Kind code	B2
Filing date	Nov 25, 2013
Priority date	Dec 11, 2012
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

A method and apparatus for flatness measuring and measuring of residual stresses in a metallic flat product ( 1 ): The method includes bending the flat product ( 1 ) in a bending device ( 3 ) such that a planar flat product ( 1 ) forms an arc ( 5 ) with a target bending radius r 0 after bending; measuring the contour and the actual bending radii r(y), in the region of the arc ( 5 ) of the bent flat product ( 1 ) at a plurality of positions along the width direction of the flat product ( 1 ); and determining the flatness of the flat product ( 1 ) taking into account the measured contour of the bent flat product ( 1 ).

First claim

The invention claimed is:

1. A method for measuring the flatness of a metallic flat product, comprising the following method steps:
bending the flat product at a location along the longitudinal direction of the flat product, so that after the bending, the planar flat product forms an arc along the location having a target bending radius r 0 ;
measuring a contour of the flat product in a region along the arc by measuring the actual bending radii r(y), in the region along the arc, of the bent flat product at a plurality of positions (y) in a width direction across the flat product; and
determining the flatness of the flat product by taking into account the measured contour of the bent flat product along the length of the arc and across the width of the flat product at the arc.

2. The method as claimed in claim 1 , further comprising measuring the contour of the flat product by measuring the actual bending radii r(x,y) of the bent flat product at a plurality of positions (x) along the longitudinal direction of the flat product; and
determining the flatness of the flat product at a number of locations (x) along the longitudinal direction of the flat product taking into account the measured contours of the bent flat product.

3. The method as claimed in, claim 1 , further comprising storing the determined flatness of the flat product and taking the stored flatness into account during further processing of the flat product.

4. A method for measuring the residual stresses of a metallic flat product comprising the following method steps:
bending the flat product, so that after the bending, a residual stress-free flat product forms an arc along the location having a target bending radius r 0 ;
measuring a contour of the flat product at the arc by measuring actual bending radii r(y), in a region along the arc, of the bent flat product in a plurality of positions(y) in a width direction across the flat product;
calculating the residual stress σ x (y) of the flat product taking into account the measured contour of the bent flat product.

5. The method as claimed in claim 4 , further comprising:
measuring the contour of the flat product at the arc by measuring the actual bending radii r(x,y), of the bent flat product in a plurality of positions (x) along the longitudinal direction of the flat product; and
calculating the residual stress σ x (x,y) of the flat product for a number of positions in the longitudinal direction (x) of the flat product taking into account the measured contours of the bent flat product.

6. The method as claimed in claim 5 , further comprising storing the residual stresses σ x of the flat product and then taking the residual stresses into account during further processing of the flat product.

7. The method as claimed in claim 1 , further comprising:
measuring an actual bending radius r optically by at least one light beam, emitting the light beam from a light source onto a surface of the flat product along the arc;
reflecting the light beam from the surface of the flat product receiving the reflected light beam by a receiver ; and
determining the distance between the light source, and the flat product and between the flat product and the receiver by the transit time of the light beam, by the phase difference between the emitted light beam and the received light beam or by means of triangulation.

8. The method as claimed in claim 7 , further comprising:
projecting a number of light beams onto a surface of the flat product along the arc for defining a light grid; and
reflecting the light beams from the surface of the flat product and receiving the reflected light beams by a camera.

9. The method as claimed in claim 7 , further comprising arranging a number of light sources and a number of receivers along the width direction (y) of the flat product along the arc and measuring the actual bending radii r(y) essentially simultaneously in the width direction (y) of the bent flat product.

10. A method for regulating the flatness of a metallic flat product, in a rolling mill, comprising the following method steps,
rolling the flat product in the rolling mill;
measuring the actual flatness P Act of the rolled flat product claimed in claim 1 ;
determining a regulating error e between a target flatness P Tar and the actual flatness P Act , e=P Tar −P Act ;
determining a correcting variable u as a function of the deviation e by means of a regulator;
applying the correcting variable u to an actuator in a rolling stand of the rolling mill, so that the regulating error e is minimized.

11. The method as claimed in claim 1 , further comprising at least one of during, shortly before, immediately before, shortly after, and immediately after measuring the contour of the bent flat product, measuring the temperature T(y) of a fiber of the flat product in the width direction (y) and taking the temperature T(y) into account when determining flatness or calculating the residual stress.

12. An apparatus for measuring flatness or for measuring the residual stresses of a metallic flat product, the apparatus comprising:
an input-side rolling conveyor located and configured for conveying the flat product;
an input-side bending device following the input side rolling conveyor and comprised of at least two entry rollers for contacting opposite surfaces of the flat product, the entry rollers being located for bending the flat product, to form a bending radius r 0 in the flat product along a longitudinal length location of the flat product;
a distance measuring device for measuring the contour at the actual bending radii r(y), of the bent flat product at a plurality of positions in a width direction (y) of the flat product; and
a computation unit for determining the flatness or the residual stresses of the flat product and the computation unit is connected to the distance measuring device for the purpose of exchanging signals.

13. The apparatus as claimed in claim 12 , wherein the distance measuring device comprises an optical, distance measuring device.

14. The apparatus as claimed in claim 12 , further comprising the distance measuring device is arranged in a vertical direction above the flat product and in a horizontal direction in the region of an apex of the arc of the bent flat product.

15. The apparatus as claimed in claim 12 , further comprising:
an output-side bending device comprised of at least two exit rollers at opposite surfaces of the flat product and located along the longitudinal length of the flat product spaced from the entry rollers and the exit rollers being configured for bending the bent flat product back toward an unbent condition; and
an output-side rolling conveyor located and configured for conveying the bent back flat product from the exit rollers.

16. The apparatus as claimed in claim 15 , further comprising at least one of the entry rollers of the input-side bending device is drivable to bend the flat product and/or driving at least one exit roller of the output-side bending device to bend back the bent flat product.

17. The apparatus as claimed in claim 15 , wherein at least one of the entry and the exit rollers are drivable so as to form an arc in the flat product along the longitudinal direction of the flat product between the entry and the exit rollers.

18. The method as claimed in claim 4 , wherein the calculation of the residual stress of the flat product takes into account the measured contours of the bent flat product according to the formula

Assignees

• Primetals Technologies Austria GmbH

Inventors

• Burger Rainer
• GRüSS ANSGAR
• Hlobil Helmut
• Hunt Peter
• Linsbod Robert

Classifications

• G01B11/16

  for measuring the deformation in a solid, e.g. optical strain gauge · CPC title

• B21B2261/06

  Width · CPC title

• B21B38/02 Primary

  for measuring flatness or profile of strips · CPC title

• G01N3/20

  by applying steady bending forces (G01N3/26, G01N3/28 take precedence) · CPC title

• B21B2003/001

  Aluminium or its alloys · CPC title