Electric resistance welding operation management device, electric resistance welding operation management method, and computer program

Patent metadata

Field	Value
Publication number	US-9446473-B2
Application number	US-201314394707-A
Country	US
Kind code	B2
Filing date	Apr 5, 2013
Priority date	Apr 18, 2012
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

An electric resistance welding operation management device manages a welding operation during manufacture of electric resistance welded steel pipe, in which heat is input to a steel plate, that is being conveyed along a specific conveyance direction and formed into a circular tube shape while pressing side faces of the metal plate with a pair of squeeze rolls, to weld together two circumferential direction edge portions of the metal plate converging in a V-shape. The electric resistance welding operation management device includes an image input section that inputs plural images and each including a Vee convergence region of the steel plate. The electric resistance welding operation management device includes a welding point position derivation section that derives the position of a welding point.

First claim

The invention claimed is:

1. An electric resistance welding operation management device that manages an electric resistance welding operation during manufacture of electric resistance welded steel pipe, in which heat is input to a metal plate, that is being conveyed along a specific conveyance direction and formed into a circular tube shape while pressing side faces of the metal plate with a pair of squeeze rolls, to weld together two circumferential direction edge portions of the metal plate converging in a V-shape, the electric resistance welding operation management device comprising a processor that causes the electric resistance welding operation management device to function as:
an image input section that is configured to input a plurality of images that are successively captured over a specific duration and each include a Vee convergence region that is a region where the metal plate converges in a V-shape;
a first position detection section that is configured, based on the images input by the image input section, to detect the position of a geometric Vee convergence point that is a geometric intersection point of the two circumferential direction edge portions of the metal plate converging in a V-shape;
a second position detection section that is configured, based on the images input by the image input section, to detect the position of a Vee convergence point that is an contact point where the two circumferential direction edge portions of the metal plate converging in a V-shape abut each other;
a welding point position derivation section that is configured, based on each of the plurality of images input by the image input section, to derive the position of a welding point, based on acquired data that takes as the position of a welding point the position, out of positions at each point in time within the specific duration, of a slit end at the furthest conveyance direction downstream point of a weld slit, having the Vee convergence point as a base point and extending further than the Vee convergence point toward the metal plate conveyance direction downstream side, at the point in time when the slit end is positioned furthest downstream in the conveyance direction;
a determination section that is configured to determine whether or not the position of the geometric Vee convergence point detected by the first position detection section and the position of the Vee convergence point detected by the second position detection section are present at different positions to each other; and
a heat input control section that is configured, when the position of the geometric Vee convergence point and the position of the Vee convergence point are determined by the determination section to be present at different positions to each other, to lower a heat input power to the metal plate in cases in which a distance between the position of the welding point derived by the welding point position derivation section and a position corresponding to an installation position of the pair of squeeze rolls has become a threshold value, or shorter.

2. The electric resistance welding operation management device of claim 1 , wherein the processor further causes the electric resistance welding operation management to function as:
a storage section that is configured, prior to the derivation of the position of a welding point being performed by the welding point position derivation section, to store in advance a distance ΔL between the position of a welding point expressed by the data obtained in advance prior to the derivation of the position of a welding point being performed by the welding point position derivation section and the position of the Vee convergence point detected by the second position detection section in advance prior to the derivation of the position of a welding point being performed by the welding point position derivation section;
wherein, the welding point position derivation section is configured to derive the position of the metal plate welding point based on the position of the Vee convergence point detected by the second position detection section when performing the derivation of the position of a welding point and the distance ΔL stored in the storage section prior to the derivation of the position of a welding point being performed by the welding point position derivation section.

3. The electric resistance welding operation management device of claim 2 , wherein the storage section is configured to store the distance ΔL for each steel type prior to the derivation of the position of a welding point being performed by the welding point position derivation section.

4. The electric resistance welding operation management device of claim 2 , wherein the processor further causes the electric resistance welding operation management to function as:
a distance ΔL derivation section that is configured to derive the distance ΔL based on the position of the Vee convergence point derived by the second position detection section, and the position of the welding point expressed by the data; and
the storage section is configured to store the distance ΔL derived by the distance ΔL derivation section before the position of the welding point is derived by the welding point position derivation section.

5. The electric resistance welding operation management device of claim 4 , wherein:
the distance ΔL derivation section is configured, based on each of a plurality of images captured over a duration that is at least longer than a fluctuation cycle of the Vee convergence point position, to derive as the distance ΔL a distance between an average position of the Vee convergence point derived by the second position detection section and the welding point position expressed by the data.

6. The electric resistance welding operation management device of claim 1 , wherein the welding point position derivation section is configured to comprise a slit end position derivation section that is configured, based on each of the plurality of images input by the image input section, to derive the position of a slit end of a weld slit for each image input by the image input section, and, out of the slit end positions derived by the slit end position derivation section, to derive the slit end position positioned furthest downstream in the conveyance direction as the position of the welding point.

7. The electric resistance welding operation management device of claim 6 , wherein the processor further causes the electric resistance welding operation management to function as:
a search region setting section that is configured to set a search region for the slit end, based on the position of the geometric Vee convergence point detected by the first position detection section, and an estimated weld line that is a weld line estimated as a bisector of a Vee convergence angle that is an angle formed between straight line approximations of regions corresponding to the circumferential direction edge portions of the Vee convergence region of the metal plate; and
the slit end position derivation section is configured to derive the position of the slit end within the search region set by the search region setting section.

8. The electric resistance welding operation management device of claim 6 , wherein each of the images input by the image input section is an image captured with an exposure time of 1/5000 sec or under.

9. The electric resistance welding operation management device of claim 6 , wherein:
out of a plurality of slit end positions derived by the slit end position derivation section, the welding point position derivation section is configured to derive a moving average value of coordinate values expressing the position of a slit end positioned furthest downstream in t

Assignees

• Nippon Steel & Sumitomo Metal Corp

Inventors

• Hasegawa Noboru
• Fukami Toshisuke
• Mizuhashi Nobuo
• Hamatani Hideki
• Karube Yoshifumi
• Miura Takao
• Tanaka Kimiharu
• Yamamoto Kazuto

Classifications

• B23K13/025

  for tubes · CPC title

• B23K11/0873 Primary

  of the longitudinal seam of tubes · CPC title

• B23K11/253 Primary

  the measured parameter being a displacement or a position · CPC title

• B23K13/08

  Electric supply or control circuits therefor · CPC title

• B21B37/78

  Control of tube rolling · CPC title