Anmol S. Birring - San Antonio TX David G. Alcazar - San Antonio TX Gary J. Hendrix - San Antonio TX John J. Hanley - San Antonio TX
Assignee:
Electric Power Research Institute - Palo Alto CA
International Classification:
G01N 2904
US Classification:
73597
Abstract:
A method for detecting hydrogen attack by ultrasound wave velocity measurements in which ultrasound waves (e. g. longitudinal, shear, or creeping) are transmitted from one transducer to another transducer along a fixed path through a steel body such as pipe. The velocity of the ultrasound wave is determined with an accuracy of 0. 1 percent from the fixed path length and the time for a wave to travel from one transducer to the other transducer. A decrease in velocity by more than two percent indicates hydrogen attack. In one embodiment, either refracted longitudinal or refracted shear waves are transmitted, and the velocities thereof are determined. In another embodiment, a creeping wave is transmitted from one transducer to the other transducer with the creeping wave including a surface wave and a subsurface wave. Travel time of the subsurface wave is measured and used with the known fixed path length in determining velocity. In the third embodiment ultrasonic waves are transmitted into the material and the backscattered ultrasound is measured.
Method Of Wear Monitoring Using Ultrasonic Phase Comparison
Hegeon Kwun - San Antonio TX Anmol S. Birring - San Antonio TX Gurvinder P. Singh - San Antonio TX Gary J. Hendrix - San Antonio TX David G. Alcazar - San Antonio TX
Assignee:
Association of American Railroads - Washington DC
International Classification:
G01M 1500
US Classification:
73119R
Abstract:
A method of monitoring the cylinder wall wear using ultrasonic phase comparison techniques is disclosed. The method comprises the steps of introducing ultrasonic waves in a cylinder wall so that the waves travel through the cylinder wall. A change in the traveling time of the ultrasonic waves traveling through the cylinder wall due to cylinder wall wear is determined. The amount of wear of the cylinder wall is calculated by multiplying the velocity of the ultrasonic waves in the cylinder wall by the traveling time change due to cylinder wall wear. The traveling time change due to cylinder wall wear is obtained by determining the actual change in travel time by a phase comparison of the traveling ultrasonic waves and adjusting the actual change in travel time to compensate for any change due to temperature variation of the cylinder wall. With this method, small changes in traveling time on the order of 10. sup. -11 second can be determined so that thickness changes due to wear on the order of 5. times. 10. sup.