Ultrasonic method and device for detecting and measuring defects in metal media
First Claim
1. A method for the measurement of abnormalities in a solid test object having opposed surfaces comprising the steps of:
- intermittently transmitting a beam of ultrasonic energy from a first location so as to cause the axis of said beam to intercept a first surface of a test object at an angle in the range of 23°
to 28°
relative to a line normal to said first surface to thereby propogate a shear mode wave and a first longitudinal mode wave in said object, said waves having substantially equal amplitudes;
reflecting said shear mode wave at a second surface of said body which is disposed generally opposite to said first surface to convert a portion of the energy comprising said shear mode wave to a second longitudinal mode wave;
serially receiving echos of said propogated first and said second longitudinal mode waves as reflected from an abnormality within the test object, said echos being received at a second location on the test object first surface which is spaced from said first location, said echos being refracted at said first surface;
acoustically isolating said trasmitted beam prior to interception of the first surface of the test object thereby from said echos subsequent to refraction thereof;
measuring the time delay transmission of a pulse of ultrasonic energy which comprises the intermittently transmitted beam and receipt of the echo commensurate with the reflection of the propogated first longitudinal wave from the abnormality; and
comparing the measured time delay with previously recorded data of time delay vrs. abonormality size to determine the distance from the test object first surface to the beginning of the abnormality.
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Accused Products
Abstract
An non-destructive testing method employs an ultrasound generator which provides a beam having an axis which intersects the outer surface of an object to be tested at an angle relative to a line normal to the surface which is in the range of 23° to 28°. A longitudinal mode wave and a shear mode wave are propogated within the object and the shear wave is converted into longitudinal mode waves by reflection from an opposite surface of the object. The propogated and mode converted waves are reflected from different portions of a defect and the echos arrive serially in time at a receiver transducer. The ultrasound generator and receiver transducer are sonically isolated. The received signals have a favorable signal-to-noise ratio and the times of receipt thereof are employed to determine the dimensions of a detected defect.
77 Citations
16 Claims
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1. A method for the measurement of abnormalities in a solid test object having opposed surfaces comprising the steps of:
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intermittently transmitting a beam of ultrasonic energy from a first location so as to cause the axis of said beam to intercept a first surface of a test object at an angle in the range of 23°
to 28°
relative to a line normal to said first surface to thereby propogate a shear mode wave and a first longitudinal mode wave in said object, said waves having substantially equal amplitudes;reflecting said shear mode wave at a second surface of said body which is disposed generally opposite to said first surface to convert a portion of the energy comprising said shear mode wave to a second longitudinal mode wave; serially receiving echos of said propogated first and said second longitudinal mode waves as reflected from an abnormality within the test object, said echos being received at a second location on the test object first surface which is spaced from said first location, said echos being refracted at said first surface; acoustically isolating said trasmitted beam prior to interception of the first surface of the test object thereby from said echos subsequent to refraction thereof; measuring the time delay transmission of a pulse of ultrasonic energy which comprises the intermittently transmitted beam and receipt of the echo commensurate with the reflection of the propogated first longitudinal wave from the abnormality; and comparing the measured time delay with previously recorded data of time delay vrs. abonormality size to determine the distance from the test object first surface to the beginning of the abnormality. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification