Quality-control method for wire/rod rolling system

Abstract

Quality of a wire or rod is controlled in a rolling mill having a succession of roll stands spaced apart in a workpiece-travel direction by a method having the first step of, before rolling a wire or rod, statically measuring a sample of at least one wire or rod with typical real roll flaws and storing the flaw data in standard format in a control computer. A single cross-sectional shape or, if there is noise, an average of a plurality of averaged cross-sectional shapes are stored standardized as polar coordinates. During actual rolling of a wire or rod its actual-shape is continuously measured and actual-shape data is generated. A similarity analysis is continuously effected by comparing the flaw data in standard format with the actual-shape data of the wire or rod being rolled. When the actual cross-sectional shape data corresponds to the flaw data, an alarm is generated.

1 . A quality-control method for wire or rod in a computer-controlled rolling mill having a succession of roll stands spaced apart in a workpiece-travel direction, the method comprising the steps of:
 before rolling a wire or rod, at least one sample wire or rod with typical real roll flaws is measured statically and flaw data in standard format is stored in a control computer, a single cross-sectional shape or, if there is noise, an average of a plurality of averaged cross-sectional shapes being stored standardized as polar coordinates;   during rolling of a wire or rod continuously measuring its actual-shape and generating actual-shape data corresponding thereto;   continuously effecting a similarity analysis by comparing the flaw data in standard format with the actual-shape data of the wire or rod being rolled; and   when the actual cross-sectional shape data corresponds to the flaw data, generating an alarm.   
   
   
       2 . The quality-control method defined in  claim 1 , further comprising the step of:
 storing and standardizing the actual-shape data prior to comparing it with the flaw data.   
   
   
       3 . The quality-control method defined in  claim 1 , further comprising the step of
 displaying a difference between the actual cross-sectional data and the flaw data.   
   
   
       4 . The quality-control method defined in  claim 1 , further comprising the step of
 measuring the temperature of the rod or wire being rolled.   
   
   
       5 . The quality-control method defined in  claim 4  wherein the actual-shape data is corrected to correspond to a cross-sectional shape the rod or wire would have at about 20° C. 
   
   
       6 . The quality-control method defined in  claim 1  wherein the rod or wire shape is measured by lasers. 
   
   
       7 . The quality-control method defined in  claim 1  wherein at least 38 angularly generally equispaced measurements of the rod or wire radius are made to determine its cross-sectional shape. 
   
   
       8 . The quality-control method defined in  claim 7  wherein 180 such angularly generally equispaced measurements are made. 
   
   
       9 . The quality-control method defined in  claim 1  wherein the determine radius portions of the wire or rod a Fourier analysis is used. 
   
   
       10 . The quality-control method defined in  claim 9  wherein a Fast Fourier analysis is used. 
   
   
       11 . The quality-control method defined in  claim 1  wherein to determine radius portions a fitting method of the actual cross section is used. 
   
   
       12 . The quality-control method defined in  claim 1  wherein minimum and maximum diameters of the wire or rod are measured at locations along its length to develop the actual-shape data. 
   
   
       13 . The quality-control method defined in  claim 1 , further comprising generating a signal representing ovalness of the rod or wire. 
   
   
       14 . The quality-control method defined in  claim 13  wherein ovalness is determined by a triangular method. 
   
   
       15 . The quality-control method defined in  claim 13  wherein ovalness is determined by a hexagonal method. 
   
   
       16 . The quality-control method defined in  claim 1  wherein the mill includes a set of calibrating roll stands and the wire or rod is measured immediately downstream therefrom. 
   
   
       17 . The quality-control method defined in  claim 1  wherein the flaw data and actual-shape data are compared by a cross correlation function. 
   
   
       18 . The quality-control method defined in  claim 1  wherein the flaw data and actual-shape data are compared by a cross covariant function. 
   
   
       19 . The quality-control method defined in  claim 1 , further comprising
 collecting flaw data regarding underfilling and overfilling or roller offset are collected and stored.   
   
   
       20 . The quality-control method defined in  claim 1  wherein for each real flaw at least two references are assigned that are set mathematically as vectors and compared with similar references for the wire or rod.