Method for ultrasonic detection of hydrogen damage in boiler tubes

Claim 1

A method of ultrasonically testing a wall of a boiler tube for detecting hydrogen damage comprising the steps of: providing a shear-wave angle-beam transmitting transducer with a frequency in the range of 2.5 MHz to 10 MHz at a first position on the outside surface of the boiler tube at a predetermined beam angle of forty-five degrees relative to the tube surface; providing a shear-wave angle-beam receiving transducer with a frequency in the range of 2.5 MHz to 10 MHz at a second position on the outside surface of the boiler tube, said second position being circumferentially spaced from and aligned with said first position, and at a predetermined beam angle of forty-five degrees relative to the tube surface; providing an adequate amount of couplant with low attenuation properties between said transducers and said outer surface of the boiler tube; transmitting an ultrasonic pulse of shear-waves of a frequency in the range of 2.5 MHz to 10 MHz into the wall of the boiler tube from the transmitting transducer to the receiving transducer along a predetermined circumferential path; measuring the relative attenuation of the amplitude of the received ultrasonic pulse; and comparing the relative attenuation of the amplitude of the received ultrasonic pulse with a known reference attenuation from an undamaged tube that does not have hydrogen damage to determine the presence of hydrogen damage.

Claim 2

A method of ultrasonically testing a wall of a boiler tube for detecting hydrogen damage comprising the steps of: providing a shear-wave angle-beam transmitting transducer with a frequency in the range of 2.5 MHz to 10 MHz at a first position on the outside surface of the boiler tube at a predetermined beam angle of forty-five degrees relative to the tube surface; providing a shear-wave angle-beam receiving transducer with a frequency in the range of 2.5 MHz to 10 MHz at a second position on the outside surface of the boiler tube, said second position being circumferentially spaced from and aligned with said first position, and at a predetermined beam angle of forty-five degrees relative to the tube surface; providing an adequate amount of couplant with low attenuation properties between said transducers and said outer surface of the boiler tube; transmitting an ultrasonic pulse of shear-waves of a frequency in the range of 2.5 MHz to 10 MHz into the wall of the boiler tube from the transmitting transducer to the receiving transducer along a predetermined circumferential path; measuring the relative attenuation of the amplitude of the received ultrasonic pulse; and comparing the relative attenuation of the amplitude of the received ultrasonic pulse with a known reference attenuation from an undamaged tube that does not have hydrogen damage to determine the presence of hydrogen damage.

Claim 4

A method of ultrasonically testing a wall of a boiler tube for detecting hydrogen damage comprising the steps of: providing a shear-wave angle beam transmitting transducer with a frequency in the range of 2.5 MHz to 10 MHz at a first position on the outside surface of the boiler tube at a predetermined beam angle of sixty degrees relative to the tube surface; providing a shear-wave angle beam receiving transducer with a frequency in the range of 2.5 MHz to 10 MHz at a second position on the outside surface of the boiler tube, said second position being axially aligned with and longitudinally spaced from said first position, and at a predetermined beam angle of sixty degrees relative to the tube surface; providing an adequate amount of couplant with low attenuation properties between said transducers and said outside surface of the boiler tube; transmitting an ultrasonic pulse of shear-waves of a frequency in the range of 2.5 MHz to 10 MHz into the wall of the boiler tube from the transmitting transducer to the receiving rransducer along a predetermined axial path; measuring the relative attenuation of the amplitude of the received ultrasonic pulse; and comparing the relative attenuation of the amplitude of the received ultrasonic pulse with a known reference attenuation from an undamaged tube that does not have hydrogen damage to determine the presence of hydrogen damage.

Claim 5

A method of ultrasonically testing a wall of a boiler tube for detecting hydrogen damage comprising the steps of: providing a shear-wave angle beam transmitting transducer with a frequency in the range of 2.5 MHz to 10 MHz at a first position on the outside surface of the boiler tube at a predetermined beam angle of sixty degrees relative to the tube surface; providing a shear-wave angle beam receiving transducer with a frequency in the range of 2.5 MHz to 10 MHz at a second position on the outside surface of the boiler tube, said second position being axially aligned with and longitudinally spaced from said first position, and at a predetermined beam angle of sixty degrees relative to the tube surface; providing an adequate amount of couplant with low attenuation properties between said transducers and said outside surface of the boiler tube; transmitting an ultrasonic pulse of shear-waves of a frequency in the range of 2.5 MHz to 10 MHz into the wall of the boiler tube from the transmitting transducer to the receiving rransducer along a predetermined axial path; measuring the relative attenuation of the amplitude of the received ultrasonic pulse; and comparing the relative attenuation of the amplitude of the received ultrasonic pulse with a known reference attenuation from an undamaged tube that does not have hydrogen damage to determine the presence of hydrogen damage.

Claim 8

A method of ultrasonically testing a wall of a boiler tube for detecting hydrogen damage comprising the steps of: providing a 0.45 MHz, center frequency, meander coil electromagnetic acoustic transducer on the outer surface of the boiler tube; energizing the electromagnetic acoustic transducer so as to introduce into the wall of the boiler tube an ultrasonic angle-beam shear-wave pulse which travels 360 degrees circumferentially around the wall of the boiler tube and which is then received by the electromagnetic acoustic transducer; measuring the relative attenuation of the amplitude of the received ultrasonic pulse; and comparing the relative attenuation of the amplitude of the received ultrasonic pulse with a known reference attenuation from an undamaged tube that does not have hydrogen damage to determine the presence of hydrogen damage.

Claim 9

A method of ultrasonically testing a wall of a boiler tube for detecting hydrogen damage comprising the steps of: providing a 0.45 MHz, center frequency, meander coil electromagnetic acoustic transducer on the outer surface of the boiler tube; energizing the electromagnetic acoustic transducer so as to introduce into the wall of the boiler tube an ultrasonic angle-beam shear-wave pulse which travels 360 degrees circumferentially around the wall of the boiler tube and which is then received by the electromagnetic acoustic transducer; measuring the relative attenuation of the amplitude of the received ultrasonic pulse; and comparing the relative attenuation of the amplitude of the received ultrasonic pulse with a known reference attenuation from an undamaged tube that does not have hydrogen damage to determine the presence of hydrogen damage.