Ultrasonic flaw detection is the use of ultrasonic energy penetration into the depth of the metal material, and from a section into another section, in the interface edge of the characteristics of the reflection to view parts of a method of shortcomings, when the ultrasonic beam from the exterior of the parts by the probe to the metal interior, encountering the shortcomings and parts of the bottom of the separate onset of reflected waves to, in the fluoroscopic screen constitutes a pulse waveform, based on these pulse waveform to discern the location and size of the shortcomings.
Ultrasonic flaw detection than X-ray flaw detection has higher flaw sensitivity, short cycle time, low cost, sensitive and convenient, high efficiency, harmless to the human body and other advantages; disadvantage is that the appearance of the work requires smooth, experienced inspectors to distinguish between the varieties of flaws, no intuitive flaws; ultrasonic flaw detection is suitable for the thickness of larger parts inspection.
The characteristics of ultrasonic flaw detection
1, ultrasonic waves in the medium to convey, in different quality interface has the characteristics of reflection, such as encountering shortcomings, the scale of the shortcomings equal to or greater than the ultrasonic wavelength, the ultrasonic waves reflected back in the shortcomings, the flaw detector can be reflected wave display; such as the scale of the shortcomings and even less than the wavelength, the sound waves will bypass the shortcomings and can not be reflected;
2, the wave sound directional good, the higher the frequency, the better the direction, to a very narrow beam of radiation to the medium, easy to confirm the location of the shortcomings.
3, the ultrasonic wave conveys large energy, such as frequency of 1MHZ (1 million Hz) of the energy conveyed by the ultrasonic wave, equivalent to the same amplitude and frequency of 1000HZ (Hz) of the sound waves 1 million times.
Ultrasonic flaw detection plate thickness of 14 mm, the interval wave amplitude curve on the connection of the three primary curves
Measuring length line Ф1 х 6 -12dB
Quantitative line Ф1 х 6 -6 dB
Judgment line Ф1 х 6 -2dB