Welding monitoring apparatus and welding monitoring method

Abstract

Provided is a welding monitoring apparatus that monitors a welding state of a V-convergence region in which a strip-shaped metal sheet is converged in a V-shape, when the metal sheet is cylindrically formed while being conveyed, and both side edges of the metal sheet are heated and melted in a manner of being butted each other while being converged in the V-shape, such that an electric resistance welded steel pipe is manufactured. This welding monitoring apparatus includes an image capturing unit that captures images of a region including the V-convergence region in time series; and an image processing unit that extracts a welding point based on the images captured in time series and detects the presence or absence and a position of irregular arcing at the welding point or on an upstream side of the welding point.

1 . A welding monitoring apparatus that monitors a welding state of a V-convergence region in which a strip-shaped metal sheet is converged in a V-shape, when the metal sheet is cylindrically formed while being conveyed, and both side edges of the metal sheet are heated and melted in a manner of being butted each other while being converged in the V-shape, such that an electric resistance welded steel pipe is manufactured, the apparatus comprising:
 an image capturing unit that captures images of a region including the V-convergence region in time series; and   an image processing unit that extracts a welding point based on the images captured in time series and detects the presence or absence and a position of irregular arcing at the welding point or on an upstream side of the welding point.   
     
     
         2 . The welding monitoring apparatus according to  claim 1 ,
 wherein the images captured by the image capturing unit are RGB images, and   wherein the image processing unit
 extracts at least one of a red image and a blue image from the RGB images, 
 performs inverted binarization and labeling of the red image with respect to the red image, and 
 detects a high-luminance portion in the blue image with respect to the blue image. 
   
     
     
         3 . The welding monitoring apparatus according to  claim 1 ,
 wherein the image capturing unit is a camera capturing 200 frames or more per second.   
     
     
         4 . A welding monitoring method for monitoring a welding state of a V-convergence region in which a strip-shaped metal sheet is converged in a V-shape, when the metal sheet is cylindrically formed while being conveyed, and both side edges of the metal sheet are heated and melted in a manner of being butted each other while being converged in the V-shape, such that an electric resistance welded steel pipe is manufactured, the method comprising:
 an image capturing step of capturing images of a region including the V-convergence region in time series; and   a detecting step of extracting a welding point based on the images captured in time series and detecting the presence or absence and a position of irregular arcing at the welding point or on an upstream side of the welding point.   
     
     
         5 . The welding monitoring method according to  claim 4 ,
 wherein RGB images are used as the images, and   wherein in the detecting step,
 at least one of a red image and a blue image is extracted from the RGB images, 
 inverted binarization and labeling of the red image are performed with respect to the red image, and 
 a high-luminance portion in the blue image is detected with respect to the blue image. 
   
     
     
         6 . The welding monitoring method according to  claim 4 ,
 wherein in the image capturing step, images are captured at a frame rate of 200 frames or more per second.   
     
     
         7 . The welding monitoring method according to  claim 4 , further comprising:
 a marking step of marking the position of the irregular arcing in a longitudinal direction in the electric resistance welded steel pipe.   
     
     
         8 . The welding monitoring method according to  claim 7 , further comprising:
 a defect presence-or-absence specifying step of performing an ultrasonic test with respect to a region to which the marking is applied.   
     
     
         9 . The welding monitoring method according to  claim 4 , further comprising:
 a tracking step of tracking the position of the irregular arcing in a longitudinal direction in the electric resistance welded steel pipe.   
     
     
         10 . The welding monitoring apparatus according to  claim 2 ,
 wherein the image capturing unit is a camera capturing 200 frames or more per second.   
     
     
         11 . The welding monitoring method according to  claim 5 ,
 wherein in the image capturing step, images are captured at a frame rate of 200 frames or more per second.   
     
     
         12 . The welding monitoring method according to  claim 5 , further comprising:
 a marking step of marking the position of the irregular arcing in a longitudinal direction in the electric resistance welded steel pipe.   
     
     
         13 . The welding monitoring method according to  claim 6 , further comprising:
 a marking step of marking the position of the irregular arcing in a longitudinal direction in the electric resistance welded steel pipe.   
     
     
         14 . The welding monitoring method according to  claim 5 , further comprising:
 a tracking step of tracking the position of the irregular arcing in a longitudinal direction in the electric resistance welded steel pipe.   
     
     
         15 . The welding monitoring method according to  claim 6 , further comprising:
 a tracking step of tracking the position of the irregular arcing in a longitudinal direction in the electric resistance welded steel pipe.   
     
     
         16 . The welding monitoring method according to  claim 11 , further comprising:
 a marking step of marking the position of the irregular arcing in a longitudinal direction in the electric resistance welded steel pipe.   
     
     
         17 . The welding monitoring method according to  claim 16 , further comprising:
 a defect presence-or-absence specifying step of performing an ultrasonic test with respect to a region to which the marking is applied.   
     
     
         18 . The welding monitoring method according to  claim 11 , further comprising:
 a tracking step of tracking the position of the irregular arcing in a longitudinal direction in the electric resistance welded steel pipe.   
     
     
         19 . The welding monitoring method according to  claim 12 , further comprising:
 a defect presence-or-absence specifying step of performing an ultrasonic test with respect to a region to which the marking is applied.   
     
     
         20 . The welding monitoring method according to  claim 13 , further comprising:
 a defect presence-or-absence specifying step of performing an ultrasonic test with respect to a region to which the marking is applied.