Non-destructive testing device for testing a welded region of a workpiece

Patent metadata

Field	Value
Publication number	US-9541526-B2
Application number	US-201214110768-A
Country	US
Kind code	B2
Filing date	Apr 5, 2012
Priority date	Apr 12, 2011
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

The device has a processor ( 20 ) that applies a magnetic field to a measurement subject ( 2 ) and after the magnetic field is discontinued, uses an induced electromotive force detector ( 17 ) to measure the magnetic fluxes emitted from multiple locations, calculates time constants of transient change of the plurality of magnetic fluxes, and detects the internal structure of the measurement subject ( 2 ) from the distribution of the time constants. The processor ( 20 ) prompts the induced electromotive force detector ( 17 ) to make first measurements at predetermined locations, prompts the induced electromotive force detector ( 17 ) to make second measurements at locations rotated by a predetermined angle from the predetermined locations, and based on the internal structure detected by the first measurements and the internal structure detected by the second measurements, estimates the center location of the nugget and/or the diameter of the nugget which has been formed inside the measurement subject ( 2 ).

First claim

The invention claimed is:

1. A non-destructive testing device, comprising:
a magnetic flux generator having an excitation controller, and
a detection processor, which are adapted to generate a magnetic flux density by applying a magnetic field to a measurement subject,
said testing device further comprising a magnetic flux detection element,
said detection processor further adapted to:
measure magnetic flux emitted from a plurality of locations on the measurement subject by way of the magnetic flux detection element,
calculate, after the magnetic field is discontinued, a plurality of time constants of transient change in magnetic flux, and
detect an internal structure of the measurement subject from a distribution state of the time constants,

wherein the magnetic flux detection element comprises a plurality of microcoils arranged in a vertical line and a horizontal line, the lines forming a cross shape,
wherein the detection processor is adapted
to dispose the magnetic flux detection element at a predetermined location on the measurement subject,
to performs a first measurement using a first subset of microcoils of the plurality of microcoils arranged in the vertical line, and
to perform a second measurement by way of a second subset of microcoils of the plurality of microcoils arranged in the horizontal line at the same location as the predetermined location, and

wherein the detection processor is adapted to estimate a center location of a nugget formed inside of the measurement subject and/or diameter of the nugget,
by calculating an intersection between: a perpendicular line passing through a central point of a connecting line of first two points extracted, by acquiring measurement results from the first measurement, and extracting from the measurement results the first two points of corresponding to two microcoils of the first subset of microcoils, the first two points corresponding to a contour line of the nugget; and
a perpendicular line passing through a central point of a connecting line of second two points extracted, by acquiring measurement results from the second measurement, and extracting from the measurement results the second two points corresponding to two microcoils of the second subset of microcoils, the second two points corresponding to the contour line of the nugget;
setting the intersection thus calculated as a center location, and calculating a diameter of a circle passing through the first two points or the second two points centering around the center location.

2. The non-destructive testing device according to claim 1 , further comprising:
an arm portion that holds a measurement device having the magnetic flux detection element; and
a drive controller adapted to move the arm portion so that the magnetic flux detection element is arranged at a predetermined location on the measurement subject serving as a measurement target.

3. The non-destructive testing device according to claim 1 , further comprising:
a display unit; and
a display controller adapted to control the display unit,
wherein the display controller is adapted to generate a virtual image of the nugget based on the center location and/or diameter of the nugget, in a case of the center location of the nugget formed inside of the measurement subject and/or the diameter of the nugget having been estimated, and to display the virtual image on the display unit.

4. The non-destructive testing device according to claim 1 , wherein the detection processor is further adapted to estimate the diameter of the nugget by calculating an average of the diameter of the circle passing through the two points of the one vertical line and the diameter of the circle passing through the two points of the one horizontal line.

5. The non-destructive testing device according to claim 4 , further comprising:
an arm portion that holds a measurement device having the magnetic flux detection element; and
a drive controller adapted to move the arm portion so that the magnetic flux detection element is arranged at a predetermined location on the measurement subject serving as a measurement target.

6. The non-destructive testing device according to claims 4 , further comprising:
a display unit; and
a display controller adapted to control the display unit,
wherein the display controller is adapted to generate a virtual image of the nugget based on the center location and/or diameter of the nugget, in a case of the center location of the nugget formed inside of the measurement subject and/or the diameter of the nugget having been estimated, and to display the virtual image on the display unit.

7. A non-destructive testing device, comprising:
a magnetic flux generator having an excitation controller, and
a detection processor which are adapted to cause a magnetic flux density to be generated by applying a magnetic field to a measurement subject, said testing device further comprising a magnetic flux detection element,
said detection processor being adapted to measure magnetic flux emitted from a plurality of locations on the measurement subject by way of the magnetic flux detection element, said detection processor further being adapted to calculate, after the magnetic field is discontinued, a plurality of time constants of transient change in magnetic flux, and to detect an internal structure of the measurement subject from a distribution state of the time constants:,
wherein the magnetic flux generator comprises a magnetic core composed of magnetic recovery portions and an excitation portion,
wherein the magnetic recovery portions are provided in a longitudinal direction of the excitation portion in parallel on both sides thereof,
wherein the magnetic flux detection element comprises a first magnetic flux detection element and a second magnetic flux detection element,
wherein the first magnetic flux detection element is arranged below the excitation portion in parallel to one magnetic recovery portion,
wherein the second magnetic flux detection element is arranged below the excitation portion in parallel to another magnetic recovery portion,
wherein the detection processor is adapted to acquire measurement results of the first magnetic flux detection element and the second magnetic flux detection element, to form a triangle by extracting from the measurement results three points that are the most distant and correspond to a contour line of a nugget, to form a circumscribed circle passing through the three points from an intersection of perpendicular bisectors on the triangle arrived at by respectively calculating perpendicular bisectors of two sides forming the triangle, to calculate a center location and diameter of the circumscribed circle, and thereby to estimate a center location of the nugget formed inside of the measurement subject and/or a diameter of the nugget, and
wherein the extracted three points represent the starting and ending point of a line segment, the line segment having a length calculated according to the number of coils detecting the nugget.

8. The non-destructive testing device according to claim 7 , further comprising:
an arm portion that holds a measurement device having the magnetic flux detection element; and
a drive controller adapted to move the arm portion so that the magnetic flux detection element is arranged at a predetermined location on the measurement subject serving as a measurement target.

9. The non-destructive testing device according to claim 7 , further comprising:
a display unit; and
a display controller adapted to control the display unit,
wherein the display controller is adapted to generate a virtual image of the nugget based on the center location and/or diameter of the nugget, in a

Assignees

• Kubota Toshihiko
• Kawanabe Osamu
• Kimura Takashi
• Okuda Atsushi
• Honda Motor Co Ltd
• Nippon Kouatsu Electric Co Ltd

Inventors

• Kubota Toshihiko
• Kawanabe Osamu
• Kimura Takashi
• Okuda Atsushi

Classifications

• G01N27/902

  by moving the sensors · CPC title

• G01N27/72 Primary

  by investigating magnetic variables · CPC title

• G01B7/12 Primary

  for measuring diameters · CPC title

• G01B7/003 Primary

  for measuring position, not involving coordinate determination (coordinate measuring G01B7/004) · CPC title

• B23K31/00

  Processes relevant to this subclass, specially adapted for particular articles or purposes, but not covered by any single one of main groups B23K1/00 - B23K28/00 · CPC title