Metal-strip warped-shape estimation method, metal-strip acceptability determination method, metal-strip manufacturing method, and metal-strip warped-shape estimation equipment

Abstract

A metal-strip warped-shape estimation method estimates, based on a shape in a width direction of a metal strip in a tension-applied state where tension in a longitudinal direction is applied, a warped shape in the width direction of the metal strip in a no-tension state where the tension is relieved. The method includes a widthwise-shape measurement step of measuring a widthwise shape distribution of the metal strip in the tension-applied state; an approximation-curve calculation step of calculating an approximation curve that approximates the widthwise shape distribution, measured in the widthwise-shape measurement step, with a quadratic curve or a circular arc; and a warped-shape estimation step of estimating the warped shape in the width direction of the metal strip in the no-tension state using the widthwise shape distribution and the approximation curve.

1 . A metal-strip warped-shape estimation method for estimating, based on a shape in a width direction of a metal strip in a tension-applied state where tension in a longitudinal direction is applied, a warped shape in the width direction of the metal strip in a no-tension state where the tension is relieved, the method comprising:
 a widthwise-shape measurement step of measuring a widthwise shape distribution of the metal strip in the tension-applied state;   an approximation-curve calculation step of calculating an approximation curve that approximates the widthwise shape distribution, measured in the widthwise-shape measurement step, with a quadratic curve or a circular arc; and   a warped-shape estimation step of estimating the warped shape in the width direction of the metal strip in the no-tension state using the widthwise shape distribution and the approximation curve.   
     
     
         2 . The metal-strip warped-shape estimation method according to  claim 1 , wherein, in the widthwise-shape measurement step, the widthwise shape distribution of the metal strip is measured by a distance measurement method or a light section method. 
     
     
         3 . The metal-strip warped-shape estimation method according to  claim 1 , wherein the widthwise-shape measurement step is executed after the metal strip is cooled by a cooling section in a continuous annealing facility and before the metal strip is wound by a coiler in the continuous annealing facility. 
     
     
         4 . A metal-strip acceptability determination method for determining acceptability of the metal strip based on the warped shape of the metal strip in the no-tension state, estimated by the metal-strip warped-shape estimation method according to  claim 1 . 
     
     
         5 . A metal-strip manufacturing method comprising:
 determining acceptability of the metal strip using the metal-strip acceptability determination method according to claim  4 ; and   manufacturing the metal strip determined to be acceptable.   
     
     
         6 . Metal-strip warped-shape estimation equipment that estimates, based on a shape in a width direction of a metal strip in a tension-applied state where tension in a longitudinal direction is applied, a warped shape in the width direction of the metal strip in a no-tension state where the tension is relieved, the metal-strip warped-shape estimation equipment comprising:
 a widthwise-shape measurement device that measures a widthwise shape distribution of the metal strip in the tension-applied state; and   a metal-strip warped-shape estimation device that estimates the warped shape in the width direction of the metal strip in the no-tension state,   wherein the metal-strip warped-shape estimation device includes: an acquisition section that acquires the widthwise shape distribution of the metal strip from the widthwise-shape measurement device; an approximation-curve calculation section that calculates an approximation curve that approximates the widthwise shape distribution, measured by the widthwise-shape measurement device, with a quadratic curve or a circular arc; and a warped-shape estimation section that estimates the warped shape in the width direction of the metal strip in the no-tension state using the widthwise shape distribution and the approximation curve.   
     
     
         7 . The metal-strip warped-shape estimation equipment according to  claim 6 , wherein the widthwise-shape measurement device measures the widthwise shape distribution of the metal strip using a distance measurement method or a light section method. 
     
     
         8 . The metal-strip warped-shape estimation equipment according to  claim 6 , wherein the widthwise-shape measurement device is disposed between a cooling section and a coiler in a continuous annealing facility that performs heat treatment on the metal strip. 
     
     
         9 . The metal-strip warped-shape estimation method according to  claim 2 , wherein the widthwise-shape measurement step is executed after the metal strip is cooled by a cooling section in a continuous annealing facility and before the metal strip is wound by a coiler in the continuous annealing facility. 
     
     
         10 . A metal-strip acceptability determination method for determining acceptability of the metal strip based on the warped shape of the metal strip in the no-tension state, estimated by the metal-strip warped-shape estimation method according to  claim 2 . 
     
     
         11 . A metal-strip acceptability determination method for determining acceptability of the metal strip based on the warped shape of the metal strip in the no-tension state, estimated by the metal-strip warped-shape estimation method according to  claim 3 . 
     
     
         12 . A metal-strip acceptability determination method for determining acceptability of the metal strip based on the warped shape of the metal strip in the no-tension state, estimated by the metal-strip warped-shape estimation method according to  claim 9 . 
     
     
         13 . A metal-strip manufacturing method comprising:
 determining acceptability of the metal strip using the metal-strip acceptability determination method according to  claim 10 ; and   manufacturing the metal strip determined to be acceptable.   
     
     
         14 . A metal-strip manufacturing method comprising:
 determining acceptability of the metal strip using the metal-strip acceptability determination method according to  claim 11 ; and   manufacturing the metal strip determined to be acceptable.   
     
     
         15 . A metal-strip manufacturing method comprising:
 determining acceptability of the metal strip using the metal-strip acceptability determination method according to claim  12 ; and   manufacturing the metal strip determined to be acceptable.   
     
     
         16 . The metal-strip warped-shape estimation equipment according to  claim 7 , wherein the widthwise-shape measurement device is disposed between a cooling section and a coiler in a continuous annealing facility that performs heat treatment on the metal strip.