What is a rail flaw detector used to detect?
The main defects in the rail are nuclear damage (white nucleus, black nucleus), crack and so on. If these defects are not found in time, they will expand and cause accidents. Special attention should be paid to the cracks in the holes at the rail joints and the transverse cracks in the rails, because these defects will easily lead to fracture of the rails. Bar and square steel, resulting in defects and inclusions, shrinkage, crack etc..
The rail can be detected by frequency modulation or pulse type flaw detector. The frequency modulation type can only detect the defects parallel to the rail surface, and the pulse type can detect the type defects. Longitudinal and transverse waves can be used to detect defects in different directions of rails. With flat probe and oblique probe in different parts of the rail detection waveform, as shown below. The position and direction of the probe are measured as the weld line is detected. Head on both sides with 35 degree oblique probe, and rail waist rail with 50 degree oblique probe.
JGT-2 type rail flaw detector is usually used for flaw detection. The horizontal probe is mainly detected by a straight probe, and the smaller inclined crack can also be found. In the detection, the probe is placed on the rail surface and the defect is judged by the presence or absence of the bottom wave of the rail. When no bottom wave is indicated, the flaw detector sends out an alarm signal. There are no defects in rail, bottom wave. When there is a horizontal defect, there is a defect wave, no bottom wave. When there is an inclined crack, the defect wave decreases or disappears, and there is no bottom wave. If there is a horizontal or inclined crack near the screw hole, there is a screw hole reflection and defect wave, but there is no bottom wave. The part of the nuclear damage available 50 degree oblique probe, available before and after the screw edge inclined crack and waist 35 degree oblique probe, the rail weld with double 35 degree oblique probe.
