Ultrasonic flaw detectors can be classified in many ways according to different classification standards.
Classification by the activity of the sound source: Active sound source flaw detector: Under the action of external force, the defects inside the object being tested actively emit sound waves, and the presence and severity of the defects are judged by the presence or absence of sound emission and the spectrum. Passive sound source flaw detector: The flaw detector itself emits ultrasonic waves, and the presence and severity of defects are judged by the presence or absence and intensity of reflected waves. Classification by the continuity of sound waves: Pulse wave flaw detector: Periodically emits discontinuous ultrasonic waves. Continuous wave flaw detector: Emit continuous ultrasonic waves, the frequency may remain unchanged or be fine-tuned within a small range. FM wave flaw detector: Emit continuous ultrasonic waves with variable frequency. Classification by the display method of defects: A-type display flaw detector: Amplitude display, used to display the presence and depth of defects. B-type display flaw detector: Image display, used to display the distribution and depth of defects on any cross section of the workpiece.
C-type display flaw detector: Image display, used to display the area of the defect, but not the depth.
Ultrasonic holographic flaw detector: Displays a three-dimensional image of the defect.
Classification by number of channels:
Single-channel flaw detector: Works alone with one (or one pair of) probes.
Multi-channel flaw detector: Works alternately with multiple (or multiple pairs of) probes, suitable for automated flaw detection.