Flaw is a defect which can lead to the fracture or breakage of the rail. Detection of flaw and removal of flaw is very important in railways. Rail flaws which cannot be detected by visual examination are detected by rail flaw detection equipments. Ultrasonic rail flaw detectors are the most common type detection device used in rail flaw detection. Crystal transducers are used here for the production of ultrasonic waves. Quartz and barium titanate are the crystal materials generally used for this purpose. We can employ two types of probes- normal probe and angle probe in ultrasonic testing. Normal probe consists of two semi-cylindrical thin crystals with a vertical separating layer through the crystals and Perspex. This probe is used for the detection of horizontal flaws, inclined flaws and bolt hole cracks. Angle probes, where crystals are mounted on angular surface are capable of transmitting pulses at an outward angle. This probe is effective in the detection of inclined and vertical defects. The five different techniques used in ultrasonic testing are frequency modulation, transmission, resonance, pulse-echo and acoustic range.
Flaw is a defect which can lead to the fracture or breakage of the rail. Detection of flaw and removal of flaw is very important in railways. Rail flaws which cannot be detected by visual examination are detected by rail flaw detection equipments. USMGo
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