Title of Invention	AN ULTRASONIC TESTING METHOD TO MAP OUT DEFECTS
Abstract	The present invention relates to an ultrasonic testing method to map out defects in an object comprising of placing the transducer (1) of the ultrasonic testing system on the object (2) so as to direct ultrasonic waves towards the probable discontinuities (3) moving the transducer (1) on the object (2) in a specific scanning mode to cover all the areas to be tested, receiving a signal in the transducer (1) representing the sound beam reflected from the discontinuity (3), displaying the received signal on a monitor, and adjusting the amplitude, of the signal to be maximum by further moving the transducer (1) in all directions, changing the amplifier gain to be at a fixed value, moving the transducer (1) in the discontinuity direction in a next position such that the amplitude remains at a maximum value and adjusting the amplitude to remain at previous value, moving the transducer (1) further till the amplitude reaches at an insignificant level although amplifier gain increases, marking the transducer position on the object (?) corresponding to the amplitude attaining zero value and determining the beam divergence for a specific transducer (1), and mapping the exact length of the discontinuity by subtracting the beam divergence for the specific transducer (1) from the beam path.

Title of Invention

AN ULTRASONIC TESTING METHOD TO MAP OUT DEFECTS

Abstract

The present invention relates to an ultrasonic testing method to map out defects in an object comprising of placing the transducer (1) of the ultrasonic testing system on the object (2) so as to direct ultrasonic waves towards the probable discontinuities (3) moving the transducer (1) on the object (2) in a specific scanning mode to cover all the areas to be tested, receiving a signal in the transducer (1) representing the sound beam reflected from the discontinuity (3), displaying the received signal on a monitor, and adjusting the amplitude, of the signal to be maximum by further moving the transducer (1) in all directions, changing the amplifier gain to be at a fixed value, moving the transducer (1) in the discontinuity direction in a next position such that the amplitude remains at a maximum value and adjusting the amplitude to remain at previous value, moving the transducer (1) further till the amplitude reaches at an insignificant level although amplifier gain increases, marking the transducer position on the object (?) corresponding to the amplitude attaining zero value and determining the beam divergence for a specific transducer (1), and mapping the exact length of the discontinuity by subtracting the beam divergence for the specific transducer (1) from the beam path.

Full Text	FIELD OF INVENTION The invention generally relates to an Ultrasonic test methodology for accurate mapping of contour of a defect. More particularly, the invention relates to a method for accurate mapping of the contour of defects in an object, for example, a raw material, semifinished and finished product, using an ultrasonic testing system. BACKGROUND OF THE INVENTION Ultrasonic testing is a well-established non-destructive testing method for evaluating the quality of raw material, semi-finished and finished products. One of the steps in the testing method is to size the discontinuity in the object so that the job can be repaired, accepted or rejected. The methodology for the sizing is as follows: The transducer is moved over the object with full contact, so that the ultrasound generated by the transducer is injected into the job at an angle or normal to the job surface. The discontinuity, if present, acts as a reflection medium and the reflected ultrasound is picked up by the same transducer and sound is converted to an electric signal. The electrical signal so obtained is amplified by an amplifier and the signal is indicated in a display device- usually a cathode ray tube or an LCD screen. Thus, the presence of the signal indicates the presence of the discontinuity. The present practice for determining the length of the discontinuity constitutes in moving the probe towards an end, for example, -position "B" of the probe so that the amplitude of the discontinuity signal is reduced by 50%. The probe is next moved in an opposite direction along the same line so that the amplitude of the signal increases to match the original value and then again drops by 50% of the amplitude of the original signal, such a position is marked as "C". The distance between the two points B and C is the length of the discontinuity. However, there is a deficiency in the existing method in which the deviation becomes high when the defects are very much curved. Secondly, the contour of the defect is also not mapped in this method. Patent US5062301 describes an automatic scanning device which includes a suspension assembly for the ultrasonic transducer and this device is basically a mechanical scanning device and not a manual scanning device. Patent US5507185 describes a technique for scanning in Ultrasonic testing, the purpose of which is to ensure that the probe is in good contact with the object being tested. This method fails to cater for the sizing of defects . In patent JP2006010314 the size of the defect is measured using a mode conversion principle of the ultrasound which is much complicated. The patent JP2005345217 adapts the principle of diffraction of sound when it encounters a defect and uses two transducers. The patent WO2005050619 (A1) describes a device wherein an array of probes are moved forwardly mechanically and reversed to reduce the noise and other scanning artificats and is very much costly and difficult to handle. OBJECTS OF THE INVENTION An object of the invention is to propose a method for accurately mapping the contour of the discontinuity in an object in an ultrasonic testing system. Another object of the invention is to propose a method for accurately mapping the contour of the discontinuity in an object in an ultrasonic testing system which is independent of gain setting of the application within a specified signal to noise ratio. An yet another object of the invention is to propose a method for accurately mapping the contour of the discontinuity in an object in an ultrasonic testing system which is capable of mapping the contour irrespective of the nature of surface of the discontinuity. A further object of the invention is to propose a method for accurately mapping the contour of the discontinuity in an object in an ultrasonic testing system which is simple and eliminates the use of sophisticated and costly devices. SUMMARY OF INVENTION The present invention provides a method for manipulating the ultrasonic transducer for mapping the contour of the discontinuity accurately in which the gain setting is not important for contour mapping of the defects. The surface finish of the discontinuity does not have any effect on the contour mapping of the discontinuity. The method eliminates the requirement of a specific reference reflector for setting the amplifier gain for testing. The local changes in microstructure within the job which affect the attenuation of sound, does not influence the result of the testing, and further does not depend upon the couplant used for testing. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Figure 1- shows a prior art method of mapping the contour of discontinuity in a job. Figure 2- shows a method of accurately mapping the contour of discontinuity in a job according to the invention. Figure 3- shows indications at different positions of the probe according to the present invention. Figure 4- shows indications on a display, of the defect at different positions of the probe, according to prior art. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION The method comprises injecting ultrasound waves into a weld by using a transducer (1), moving the transducer (1) in a specific scanning pattern depending on a location of defect (3) as indicated in Fig 2. For an illustration of the invention, the job (2) is shown as a weld, but the method can be extended to any product starting from a casting, a forging, and other similar products. A reference block with an side drilled hole reflector is provide. The transducer is kept on the block and it is moved so that the maximum amplitude echo is received. The position is marked as PI. The amplifier gain is increased to make the echo reach 80% of screen. The transducer is moved forward till the echo height reaches 20 % of screen height. The amplifier gain is again increased till the echo height reaches 80%. The transducer is again moved till it reaches 20 %. Again the amplifier gain is increased to make the echo height reach 80%. This sequence is repeated till the reflection reaches a level compared to the noise in the system or till the echo vanishes. The position of transducer at that point is marked as P2. The same sequence is repeated in the reverse direction and position is marked as P3. For that beam path, the distance P2- PI is the beam divergence correction factor in the forward direction and P3 - PI is the beam divergence correction factor in the reverse direction. This beam correction factor for horizontal beam divergence. This procedure is repeated for vertical beam divergence also to ascertain the correction factor. The beam width correction factor is ascertained for different beam paths of the holes. The method further includes placing the transducer (1) on the job (2) such that the ultrasound is directed towards the probable discontinuities (3). The transducer (1) is moved such that the ultrasound beam covers all the areas to be tested. When the sound beam hits a discontinuity, it is reflected and is received by the transducer (1) and the received signal is displayed on a monitor. The signal amplitude is adjusted by moving the transducer (1) in all the directions such that the signal amplitude is the maximum. The gain of the amplifier is changed such that the amplitude is at a fixed value, say 80% of the screen height. The transducer (1) is moved to the next position along the discontinuity direction such that the amplitude is always maximum for that position. The amplifier gain is again changed so that the amplitude remains at the previous value i.e. at 80% of screen height. The transducer (1) is moved in all the directions till the amplitude is at a very low level even when the amplifier gain is increased. As the amplitude is becoming zero, the transducer location is marked on the job(2). The beam width correction factor is to be ascertained for a specific probe (1) by adopting the method mentioned in the previous paragraph. The exact contour of the discontinuity (3) is mapped by subtracting the beam divergence for that particular probe (1), for that material, for that beam path. Fig 2 illustrates the scanning pattern. In Fig.2 after identifying the position of the probe (E), the beam divergence correction ascertained as per the procedure given in the previous paragraph is subtracted and the location of the end of the defect is identified as G as shown in the fig. The same procedure is repeated on the other end of the defect and the location of the other end of the defect is identified as H. From the path of the probe at every point the contour of the discontinuity is drawn. WE CLAIM 1. A method for accurately mapping the contour of discontinuity in an object in an ultrasonic testing system, comprising: - placing the transducer of the ultrasonic testing system on the object so as to direct the ultrasound waves towards the probable discontinuities: - moving the transducer on the object in a specific scanning mode to cover all the areas to be tested; - receiving a signal in the transducer representing the sound beam reflected from the discontinuity; - displaying the received signal on the monitor, and adjusting the amplitude of the signal to be maximum by further moving the transducer in all directions; - changing the amplifier gain to be at a fixed value; - moving the transducer in the discontinuity direction in a next position such that the amplitude remains at a maximum value, and adjusting the amplitude to remain at the previous value; - moving the transducer further till the amplitude reaches at an insignificant level although amplifier gain increases; - marking the transducer position on the object corresponding to the amplitude attaining zero value; - determining the beam divergence for a specific transducer, and mapping the exact length of the discontinuity by subtracting the beam divergence for the specific transducer from the beam path; characterised in that the exact contour of the discontinuity is determined by subtracting corresponding beam divergence for the specific transducer . from the beampath. 2. A method for accurately mapping the contour of discontinuity in an object in an ultrasonic testing system procedure as substantially described and illustrated herein with reference to the accompanying drawings. ABSTRACT TITLE: AN ULTRASONIC TESTING METHOD TO MAP OUT DEFECTS The present invention relates to an ultrasonic testing method to map out defects in an object comprising of placing the transducer (1) of the ultrasonic testing system on the object (2) so as to direct ultrasonic waves towards the probable discontinuities (3) moving the transducer (1) on the object (2) in a specific scanning mode to cover all the areas to be tested, receiving a signal in the transducer (1) representing the sound beam reflected from the discontinuity (3), displaying the received signal on a monitor, and adjusting the amplitude, of the signal to be maximum by further moving the transducer (1) in all directions, changing the amplifier gain to be at a fixed value, moving the transducer (1) in the discontinuity direction in a next position such that the amplitude remains at a maximum value and adjusting the amplitude to remain at previous value, moving the transducer (1) further till the amplitude reaches at an insignificant level although amplifier gain increases, marking the transducer position on the object (?) corresponding to the amplitude attaining zero value and determining the beam divergence for a specific transducer (1), and mapping the exact length of the discontinuity by subtracting the beam divergence for the specific transducer (1) from the beam path.

Full Text

FIELD OF INVENTION
The invention generally relates to an Ultrasonic test methodology for accurate mapping of contour of a defect. More particularly, the invention relates to a method for accurate mapping of the contour of defects in an object, for example, a raw material, semifinished and finished product, using an ultrasonic testing system.
BACKGROUND OF THE INVENTION
Ultrasonic testing is a well-established non-destructive testing method for evaluating the quality of raw material, semi-finished and finished products.
One of the steps in the testing method is to size the discontinuity in the object so that the job can be repaired, accepted or rejected. The methodology for the sizing is as follows: The transducer is moved over the object with full contact, so that the ultrasound generated by the transducer is injected into the job at an angle or normal to the job surface. The discontinuity, if present, acts as a reflection medium and the reflected ultrasound is picked up by the same transducer and sound is converted to an electric signal. The electrical signal so obtained is amplified by an amplifier and the signal is indicated in a display device- usually a cathode ray tube or an LCD screen. Thus, the presence of the signal indicates the presence of the discontinuity.

The present practice for determining the length of the discontinuity constitutes in moving the probe towards an end, for example, -position "B" of the probe so that the amplitude of the discontinuity signal is reduced by 50%. The probe is next moved in an opposite direction along the same line so that the amplitude of the signal increases to match the original value and then again drops by 50% of the amplitude of the original signal, such a position is marked as "C". The distance between the two points B and C is the length of the discontinuity.
However, there is a deficiency in the existing method in which the deviation becomes high when the defects are very much curved. Secondly, the contour of the defect is also not mapped in this method.
Patent US5062301 describes an automatic scanning device which includes a suspension assembly for the ultrasonic transducer and this device is basically a mechanical scanning device and not a manual scanning device.
Patent US5507185 describes a technique for scanning in Ultrasonic testing, the purpose of which is to ensure that the probe is in good contact with the object being tested. This method fails to cater for the sizing of defects .
In patent JP2006010314 the size of the defect is measured using a mode conversion principle of the ultrasound which is much complicated.

The patent JP2005345217 adapts the principle of diffraction of sound when it encounters a defect and uses two transducers.
The patent WO2005050619 (A1) describes a device wherein an array of probes are moved forwardly mechanically and reversed to reduce the noise and other scanning artificats and is very much costly and difficult to handle.
OBJECTS OF THE INVENTION
An object of the invention is to propose a method for accurately mapping the contour of the discontinuity in an object in an ultrasonic testing system.
Another object of the invention is to propose a method for accurately mapping the contour of the discontinuity in an object in an ultrasonic testing system which is independent of gain setting of the application within a specified signal to noise ratio.
An yet another object of the invention is to propose a method for accurately mapping the contour of the discontinuity in an object in an ultrasonic testing system which is capable of mapping the contour irrespective of the nature of surface of the discontinuity.

A further object of the invention is to propose a method for accurately mapping the contour of the discontinuity in an object in an ultrasonic testing system which is simple and eliminates the use of sophisticated and costly devices.
SUMMARY OF INVENTION
The present invention provides a method for manipulating the ultrasonic transducer for mapping the contour of the discontinuity accurately in which the gain setting is not important for contour mapping of the defects. The surface finish of the discontinuity does not have any effect on the contour mapping of the discontinuity. The method eliminates the requirement of a specific reference reflector for setting the amplifier gain for testing. The local changes in microstructure within the job which affect the attenuation of sound, does not influence the result of the testing, and further does not depend upon the couplant used for testing.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1- shows a prior art method of mapping the contour of discontinuity in a job.

Figure 2- shows a method of accurately mapping the contour of discontinuity in a job according to the invention.
Figure 3- shows indications at different positions of the probe according to the present invention.
Figure 4- shows indications on a display, of the defect at different positions of the probe, according to prior art.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
The method comprises injecting ultrasound waves into a weld by using a transducer (1), moving the transducer (1) in a specific scanning pattern depending on a location of defect (3) as indicated in Fig 2. For an illustration of the invention, the job (2) is shown as a weld, but the method can be extended to any product starting from a casting, a forging, and other similar products.
A reference block with an side drilled hole reflector is provide. The transducer is kept on the block and it is moved so that the maximum amplitude echo is received. The position is marked as PI. The amplifier gain is increased to make the echo reach 80% of screen. The transducer is moved forward till the echo

height reaches 20 % of screen height. The amplifier gain is again increased till the echo height reaches 80%. The transducer is again moved till it reaches 20 %. Again the amplifier gain is increased to make the echo height reach 80%. This sequence is repeated till the reflection reaches a level compared to the noise in the system or till the echo vanishes. The position of transducer at that point is marked as P2. The same sequence is repeated in the reverse direction and position is marked as P3. For that beam path, the distance P2- PI is the beam divergence correction factor in the forward direction and P3 - PI is the beam divergence correction factor in the reverse direction. This beam correction factor for horizontal beam divergence. This procedure is repeated for vertical beam divergence also to ascertain the correction factor. The beam width correction factor is ascertained for different beam paths of the holes.
The method further includes placing the transducer (1) on the job (2) such that the ultrasound is directed towards the probable discontinuities (3). The transducer (1) is moved such that the ultrasound beam covers all the areas to be tested. When the sound beam hits a discontinuity, it is reflected and is received by the transducer (1) and the received signal is displayed on a monitor. The signal amplitude is adjusted by moving the transducer (1) in all the directions such that the signal amplitude is the maximum. The gain of the amplifier is

changed such that the amplitude is at a fixed value, say 80% of the screen height. The transducer (1) is moved to the next position along the discontinuity direction such that the amplitude is always maximum for that position. The amplifier gain is again changed so that the amplitude remains at the previous value i.e. at 80% of screen height. The transducer (1) is moved in all the directions till the amplitude is at a very low level even when the amplifier gain is increased. As the amplitude is becoming zero, the transducer location is marked on the job(2). The beam width correction factor is to be ascertained for a specific probe (1) by adopting the method mentioned in the previous paragraph.
The exact contour of the discontinuity (3) is mapped by subtracting the beam divergence for that particular probe (1), for that material, for that beam path. Fig 2 illustrates the scanning pattern. In Fig.2 after identifying the position of the probe (E), the beam divergence correction ascertained as per the procedure given in the previous paragraph is subtracted and the location of the end of the defect is identified as G as shown in the fig. The same procedure is repeated on the other end of the defect and the location of the other end of the defect is identified as H. From the path of the probe at every point the contour of the discontinuity is drawn.

WE CLAIM
1. A method for accurately mapping the contour of discontinuity in an object in an ultrasonic testing system, comprising:
- placing the transducer of the ultrasonic testing system on the object so as
to direct the ultrasound waves towards the probable discontinuities:
- moving the transducer on the object in a specific scanning mode to cover
all the areas to be tested;
- receiving a signal in the transducer representing the sound beam reflected
from the discontinuity;
- displaying the received signal on the monitor, and adjusting the amplitude
of the signal to be maximum by further moving the transducer in all
directions;
- changing the amplifier gain to be at a fixed value;
- moving the transducer in the discontinuity direction in a next position such
that the amplitude remains at a maximum value, and adjusting the
amplitude to remain at the previous value;
- moving the transducer further till the amplitude reaches at an insignificant
level although amplifier gain increases;

- marking the transducer position on the object corresponding to the
amplitude attaining zero value;
- determining the beam divergence for a specific transducer, and mapping
the exact length of the discontinuity by subtracting the beam divergence
for the specific transducer from the beam path;
characterised in that the exact contour of the discontinuity is determined by subtracting corresponding beam divergence for the specific transducer . from the beampath.
2. A method for accurately mapping the contour of discontinuity in an object in an ultrasonic testing system procedure as substantially described and illustrated herein with reference to the accompanying drawings.

ABSTRACT

TITLE: AN ULTRASONIC TESTING METHOD TO MAP OUT DEFECTS
The present invention relates to an ultrasonic testing method to map out defects in an object comprising of placing the transducer (1) of the ultrasonic testing system on the object (2) so as to direct ultrasonic waves towards the probable discontinuities (3) moving the transducer (1) on the object (2) in a specific scanning mode to cover all the areas to be tested, receiving a signal in the transducer (1) representing the sound beam reflected from the discontinuity (3), displaying the received signal on a monitor, and adjusting the amplitude, of the signal to be maximum by further moving the transducer (1) in all directions, changing the amplifier gain to be at a fixed value, moving the transducer (1) in the discontinuity direction in a next position such that the amplitude remains at a maximum value and adjusting the amplitude to remain at previous value, moving the transducer (1) further till the amplitude reaches at an insignificant level although amplifier gain increases, marking the transducer position on the object (?) corresponding to the amplitude attaining zero value and determining the beam divergence for a specific transducer (1), and mapping the exact length of the discontinuity by subtracting the beam divergence for the specific transducer (1) from the beam path.

Documents:

00034-kol-2007 correspondence.pdf

00034-kol-2007 form-18.pdf

0034-kol-2007 abstract.pdf

0034-kol-2007 claims.pdf

0034-kol-2007 correspondence others.pdf

0034-kol-2007 description(complete).pdf

0034-kol-2007 drawings.pdf

0034-kol-2007 form-1.pdf

0034-kol-2007 form-2.pdf

0034-kol-2007 form-3.pdf

34-KOL-2007-ABSTRACT.pdf

34-KOL-2007-AMENDED CLAIMS.pdf

34-KOL-2007-CANCELLED PAGES-1.1.pdf

34-KOL-2007-CANCELLED PAGES.pdf

34-KOL-2007-CORRESPONDENCE.pdf

34-KOL-2007-DESCRIPTION (COMPLETE).pdf

34-KOL-2007-EXAMINATION REPORT.pdf

34-KOL-2007-FORM 1.pdf

34-KOL-2007-FORM 18.pdf

34-KOL-2007-FORM 2.pdf

34-KOL-2007-FORM 3.pdf

34-KOL-2007-FORM 5.pdf

34-KOL-2007-GPA.pdf

34-KOL-2007-GRANTED-ABSTRACT.pdf

34-KOL-2007-GRANTED-CLAIMS.pdf

34-KOL-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

34-KOL-2007-GRANTED-DRAWINGS.pdf

34-KOL-2007-GRANTED-FORM 1.pdf

34-KOL-2007-GRANTED-FORM 2.pdf

34-KOL-2007-GRANTED-FORM 3.pdf

34-KOL-2007-GRANTED-FORM 5.pdf

34-KOL-2007-GRANTED-SPECIFICATION-COMPLETE.pdf

34-KOL-2007-REPLY TO EXAMINATION REPORT.pdf

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Patent Number

258361

Indian Patent Application Number

34/KOL/2007

PG Journal Number

01/2014

Publication Date

03-Jan-2014

Grant Date

02-Jan-2014

Date of Filing

10-Jan-2007

Name of Patentee

BHARAT HEAVY ELECTRICALS LIMITED

Applicant Address

REGIONAL OFFICES AT REGIONAL OPERATIONS DIVISION (ROD), PLOT NO: 9/1,DJ BLOCK 3RD FLOOR, KARUNAMOYEE, SALT LAKE CITY, KOLKATA-700091. REGISTERED OFFICE AT BHEL HOUSE, SIRI FORT, NEW DELHI-110049

Inventors:

#	Inventor's Name	Inventor's Address
1	NAGAMUTHU DHANASEKARAN	WELDING RESEARCH INSTITUTE, BHEL, TIRUCHIRAPPALLI 620014
2	SRINIVASAN SURESH	WELDING RESEARCH INSTITUTE, BHEL, TIRUCHIRAPPALLI 620014
3	GANAPATHY UMASHANKER	WELDING RESEARCH INSTITUTE, BHEL, TIRUCHIRAPPALLI 620014
4	SETHURAMA SRINIVASA ANANTHAN	WELDING RESEARCH INSTITUTE, BHEL, TIRUCHIRAPPALLI 620014

PCT International Classification Number

G01S7/521

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA