·White spot

The defect wave is a forest shaped wave with clear and sharp peaks. The location of the damage wave corresponds to the distribution of defects. When the probe moves, the damage wave switches and changes slowly. When the sensitivity of ultrasonic testing is reduced, the damage wave decreases slower than the bottom wave. The white spot has a significant impact on the number of reflections of the bottom wave, and the bottom wave may disappear 1-2 times or even disappear. When increasing sensitivity, there is no significant increase in the number of bottom waves. The waveform of the flaw detection around the circumference is similar. During longitudinal inspection, the damage wave will not continue to the end of the forging blank.

·Internal crack

1. In the detection of transverse internal cracks in axial workpieces with transverse internal cracks, when the sound velocity is parallel to the crack, there is no bottom wave or damage wave. After increasing sensitivity, a series of small damage waves appear. When the probe is moved away from the crack, the bottom wave reflects multiple times and returns to normal. The axial movement of the oblique probe for flaw detection and the longitudinal penetration of the straight probe both exhibit typical crack waveforms, namely strong waveform reflection, wide wave bottom, branched wave peaks, and bundled shapes. When the angle probe moves towards the crack, the damage wave moves towards the initial wave, and vice versa, it moves away from the initial wave direction.

2. The central forging crack damage wave is a strong pulse at the center. When the probe is moved in the circumferential direction, the amplitude of the damage wave changes greatly, sometimes strong and sometimes weak, and the number of bottom waves is very small or the bottom wave disappears.

3. Longitudinal internal cracks in axial forgings, with a straight probe for circumferential flaw detection. When the sound beam is parallel to the crack, there is no bottom wave or damage wave. When the probe rotates 90 °, the reflected wave is strong, showing a crack waveform. Sometimes there may be secondary reflection of the crack, and generally there is no bottom wave. The bottom wave and damage wave exhibit special patterns of change

·Shrinkage cavity

　　Ultrasonic manufacturerThe analysis shows that the reflection of the damage wave is strong, the bottom of the wave is wide, and it is bundled. There are often small damage waves near the main damage wave, which have a serious impact on the bottom wave and often cause it to disappear. The damage waves around the circumference are basically similar, and shrinkage holes often appear at the riser end or hot junction.

·Residual shrinkage cavity

The amplitude of the damage wave is strong and appears in the center of the workpiece. During axial flaw detection, the damage wave has continuity. Due to shrinkage forging deformation, the amplitude of the damage wave varies greatly around the circumference, and defects cause severe attenuation or even disappearance of the bottom wave.

·Loose

The looseness in forgings has very low or no damage waves at low sensitivity, and only shows a typical looseness waveform after increasing sensitivity. The central looseness often occurs in the heart, and generally appears between the initial wave and the bottom wave. The looseness has a certain impact on the bottom wave, but the impact is not significant. As the sensitivity increases, the number of bottom waves increases significantly. The looseness in castings has a significant absorption and scattering effect on sound waves, often significantly reducing or even disappearing the bottom wave. Severe looseness has neither bottom wave nor damage wave, and when the probe moves, a creeping waveform with a very low peak will appear.