Standard depth of penetration
The standard depth of penetration is the point in a material where the eddy current density has dropped to about 37 % of its surface value. It determines the depth to which flaws can be detected.
Physical-Chemical Mechanism of Action
The Standard Depth of Penetration (SET) marks the point in a material where the eddy current density has dropped to about 37 % of its surface value. This value indicates how deep into the material the electrons of the ultrasonic pulse penetrate and are still detectable.
Metallurgical Relevance & Welding Risks
The SET determines the depth to which flaws or defects in the material are detectable. With a penetration depth of 1 mm, pressure tests on bottles with a diameter of 25 mm can be used. A SET that is too low can cause smaller defects not to be detected, while a SET that is too high makes testing more complicated and may produce false positives.
Workshop Practice & Instructions
To correctly determine the Standard Depth of Penetration, use an ultrasonic device with the appropriate frequency. For the bottle pressure test with a diameter of 25 mm, a SET of at least 1 mm is required. Ensure that the test device is properly calibrated and that measurement conditions are optimal to achieve accurate results.