Methods for ultrasonic inspection of spot and seam resistance welds in metallic sheets and a spot weld examination probe system (SWEPS)

• US 6,948,369 B2
• Filed: 01/12/2005
• Issued: 09/27/2005
• Est. Priority Date: 02/06/2002
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Fleming, Marvin F., Clark, Jack P.
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US11/034,674
• Publication Number:
  US 20050132809A1
• Time in Patent Office: 258 Days
• Field of Search: 735/88, 735/97, 735/98, 736/20, 736/44, 228/104
• US Class Current: 73/588
• CPC Class Codes: G01N 2203/0296 Welds
• CPC Class Codes: G01N 2291/0234 Metals, e.g. steel
• CPC Class Codes: G01N 2291/0237 Thin materials, e.g. paper, membranes, thin films
• CPC Class Codes: G01N 2291/02854 Length, thickness
• CPC Class Codes: G01N 2291/044 Internal reflections (echoes), e.g. on walls or defects
• CPC Class Codes: G01N 2291/2672 Spot welding
• CPC Class Codes: G01N 2291/2675 Seam, butt welding
• CPC Class Codes: G01N 29/0645 Display representation or displayed parameters, e.g. A-, B- or C-Scan
• CPC Class Codes: G01N 29/07 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/2456 Focusing probes focusing arrangements G01N29/221
• CPC Class Codes: G01N 29/265 by moving the sensor relative to a stationary material
• CPC Class Codes: G01N 3/00 Investigating strength properties of solid materials by application of mechanical stress

Abstract

An external focused ultrasonic beam, non-destructive, open-air, inspection method of sheet metal spot and seam weldments using a probe in combination with motion measurement of the probe over the weldments during inspection without immersion of the material. Reflected ultrasonic waves are received and signals produced and processed or displayed as A-scan, B-scan and C-scan images that are easily recognized. An A-Scan is based on the time-of-flight difference between the outer surface, the weldment and inner and opposite surfaces of the component. B-scan and C-scan indicate the degree of weld fusion and provide data relative to fused thickness and defects sheet metal or welds. A special purpose scanner that enables ultrasonic examination welds. Scanner is pencil like ultrasonic probe with bearing face and position sensing device disposed adjacent a weld position. Scanner collects data for method to determine various characteristics of welded items.

Claims

1. A non-destructive, non-immersion, open air method for ultrasonically measuring a weldment between materials, the method comprises the steps of:

a. selecting an ultrasonic signal sending and receiving probe with an ultrasonic transducer and a nose piece sized to be substantially the same size as an electrode indentation corresponding to the weldment to be measured;

b. placing the nose piece of the ultrasonic signal sending and receiving probe on an external surface of the material;

c. transporting said probe in a selected path along the external surface of the material with the nose piece sliding on high points of the material to maintain the ultrasonic transducer of the probe a fixed stand-off distance from the external surface of the material as ultrasonic signals are applied to and received from the surface of the material;

d. determining time between each ultrasonic signal applied to the external surface and each ultrasonic signal received from the external surface;

e. measuring distance traveled by the probe along the path with the measured distance travel coordinated in time application and receipt of ultrasonic signals to and from the material; and

f. determining weldment characteristics from the results obtained in steps d. and e.

2. The method as in claim 1 further comprising the step of:

g. providing and maintaining a couplant between the nose piece and external surface of the material.

3. The method as in claim 1 wherein the nose piece provides a steady reference against the external surface of the material, allowing accurate measurements of the surface, thickness and electrode impression of the material.

4. The method as in claim 1 wherein the nose piece continuously follows the external surface of the material.

5. The method as in claim 1 wherein step f. includes the steps of generating of A, B and C scans of the material.

6. The method as in claim 1 wherein step f. includes the steps of:

g. determining the thickness of the material;

h. determining a diameter of the weldment;

I. determining a dimension of a external surface impression caused by a spot welding electrode when forming the weldment;

j. determining an indentation depth caused by the spot welding electrode when forming the weldment;

k. determining the extent of distortion of the external surface of the material caused during forming the weldment;

l. determining the yield of acceptable weldments from a group of inspected weldments; and

m. detecting cracks, holes, porosity, non-metallic inclusions and indentation of weldments and at weldment sites.

7. An ultrasonic scanner to open air, non-destructively scan an external surface of a material to generate data to determine characteristics of weldments in the material comprising:

an ultrasonic transducer to generate and receive ultrasonic signals applied to and received from the external surface of the material;

a body sized and shaped to hold the ultrasonic transducer and having a nose piece to interface with the external surface of the material to direct signals from the ultrasonic transducer to the surface and to focus ultrasonic signals received from the surface onto the ultrasonic transducer; and

a distance measurement device in contact with the surface of the material to determine travel distance of the body at any point in time as the body is transported across the surface of the material;

wherein said nose piece is sized to be substantially the same size as an electrode indentation corresponding to the weldment to be measured with the nose piece sliding on high points of the material to maintain the ultrasonic transducer a fixed stand-off distance from the external surface of the material.

8. The ultrasonic scanner as in claim 7 further comprising a couplet means to provide and maintain a couplant between the nose piece and the surface of the material.

9. The ultrasonic scanner as in claim 7 wherein the nose piece is sized to provide a steady reference against the external surface of the material, allowing accurate measurements of the surface, thickness and electrode impression of the material.

10. The ultrasonic transducer as in claim 7 wherein the nose piece surface is sized and shaped to continuously follow the external surface of the material.

11. A non-destructive, open air measurement system to non-destructively determine characteristics of weldments in a material, without immersion of the material, comprising:

a scanner including;

an ultrasonic transducer to generate and receive ultrasonic signals applied to and received from the external surface of the material;

a body sized and shaped to hold the ultrasonic transducer and having a nose piece to interface with the external surface of the material to direct signals from the ultrasonic transducer to the surface and to focus ultrasonic signals received from the surface onto the ultrasonic transducer; and

a distance measurement device in contact with the surface of the material to determine travel distance of the body at any point in time as the body is transported across the surface of the material;

wherein said nose piece is sized to be substantially the same size as an electrode indentation corresponding to the weldment to be measured with the nose piece sliding on high points of the material to maintain the ultrasonic transducer a fixed stand-off distance from the external surface of the material; and

a processor coupled to the scanner to;

trigger the scanner to transmit an ultrasonic signal to the surface of the material;

receive a signal from the scanner for each ultrasonic signal being received from the material;

receive signals from the scanner corresponding to the position of the scanner at least whenever the scanner is triggered to send signals to the material and when the scanner receives signals from the material; and

determine characteristics of the weldment from the timing signals and scanner travel distance.

12. The measurement system as in claim 11, the scanner further comprising a couplet means to provide and maintain a couplant between the nose piece and the surface of the material.

13. The measurement system as in claim 11 wherein the nose piece of the scanner acts is sized to provide a steady reference against the external surface of the material, allowing accurate measurements of the surface, thickness and electrode impression of the material.

14. The measurement system as in claim 11 wherein the of the scanner nose piece surface is sized and shaped to follow the external surface of the material.

15. The measurement system as in claim 11 wherein the processor generates of A, B and C scans of the material.

16. The measurement system as in claim 11 wherein the processor determines the thickness of the material, a diameter of the weldment, a dimension of a external surface impression caused by a spot welding electrode when forming the weldment, an indentation depth caused by the spot welding electrode when forming the weldment, the external surface of the material caused during forming the weldment, the yield of acceptable weldments from a group of inspected weldments, and detects cracks, holes, porosity, non-metallic inclusions and indentation of weldments and at weldment sites.