ULTRASONIC TESTING - satecosas.it · UNI EN 583-4 Examination of discontinuities perpendicular to...
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ULTRASONIC TESTING 1 Method: UT exploits the principle of sound propagation in an elastic body by the vibration of atoms and molecules that compose it with frequency between 1 and 10 MHz (not perceptible to the human ear), transmitted with a speed depending on the mechanical characteristics of the material traversed. It identifies defects both superficial and internal to the volume, by specifying the distance and size, and, finally, to measure the thickness . The waves generated can be transverse type (front perpendicular to the direction of the excited particles) and longitudinal type (parallel oscillation of the particles of the material according to the direction of wave propagation), which has a penetration capacity proportional to their frequency. MAIN ELEMENTS Ultrasonic ( transmitter/receiver ) Piezoelectric sensor (transducer) Means coupling PROCEDURE Preparation of the surface Choice of the probe Calibration scale/amplitude ultrasonic instrument Application by interference PRINCIPLES OF THE METHOD The starting signal (called "eco start ") and the one reflecting from the opposite surface to the entry (called "eco background ") are displayed on the instrument through the peaks, whose distance is proportional to the time taken by the ultrasound to travel the trip back from the probe to the reflective surface inside the material. If during this process, the ultrasound beam encounters a discontinuity, it will be reflected, absorbed, deflected between the two previous peaks (echo start and echo end).
Transcript of ULTRASONIC TESTING - satecosas.it · UNI EN 583-4 Examination of discontinuities perpendicular to...
ULTRASONIC TESTING
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Method: UT exploits the principle of sound propagation in an elastic body by the vibration of atoms and molecules that compose it with frequency between 1 and 10 MHz (not perceptible to the human ear), transmitted with a speed depending on the mechanical characteristics of the material traversed. It identifies defects both superficial and internal to the volume, by specifying the distance and size, and, finally, to measure the thickness . The waves generated can be transverse type (front perpendicular to the direction of the excited particles) and longitudinal type (parallel oscillation of the particles of the material according to the direction of wave propagation), which has a penetration capacity proportional to their frequency. MAIN ELEMENTS -‐ Ultrasonic ( transmitter/receiver ) -‐ Piezoelectric sensor (transducer) -‐ Means coupling PROCEDURE -‐ Preparation of the surface -‐ Choice of the probe -‐ Calibration scale/amplitude ultrasonic instrument -‐ Application by interference PRINCIPLES OF THE METHOD The starting signal (called "eco start ") and the one reflecting from the opposite surface to the entry (called "eco background ") are displayed on the instrument through the peaks, whose distance is proportional to the time taken by the ultrasound to travel the trip back from the probe to the reflective surface inside the material. If during this process, the ultrasound beam encounters a discontinuity, it will be reflected, absorbed, deflected between the two previous peaks (echo start and echo end).
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The monitoring results are stored on the ultrasonic instrument and reported on the final report of the controlled component.
EXAMPLE SHOWN ON CERTIFICATE OF ULTRASOUND
EXAMPLES OF ULTRASONIC INSPECTION
Control of the welding junction of a rail with probe angled 70°.
ULTRASONIC TESTING
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Control of a shaft of a gearbox by probe transversal waves
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Thickness check of a sheet-‐metal box (internal control of corrosion)
NORMATIVE REFERENCES UNI EN 10228-3 Control of ferritic or martensitic steel forgings UNI EN 10228-4 Control of forgings of ferritic-austenitic stainless steel UNI EN 583-1 General principles UNI EN 583-3 Technique for transmission UNI EN 583-4 Examination of discontinuities perpendicular to the surface UNI EN 583-5 Characterization and sizing of discontinuities UNI EN ISO 11666 Levels of acceptability for ultrasonic welds full penetration UNI EN ISO 17640 Control techniques, levels of testing and evaluation UNI EN ISO 23279 Characterization of indications in welds UNI EN 10160 Control of steel flat products with thickness more than 6mm (reflection method) UNI EN 14127 Measurement of thickness by ultrasound
