Detection method for rail bottom cracks of steel rail through ultrasonic flaw detection

Abstract

The invention relates to a steel rail ultrasonic flaw detection rail bottom crack detection method, and belongs to the technical field of heavy rail ultrasonic flaw detection methods. According to the technical scheme, the rail bottom of the steel rail is automatically cleaned, and misinformation is avoided; a proper probe box is selected and adjusted, and the sound path distance of waveform conversion is ensured; waveform conversion is conducted through a water immersion method, and longitudinal waves in water are converted into transverse waves in steel; after waveform conversion is completed, scanning the rail bottom of the steel rail by using a secondary transverse wave signal to find defect waves; after the damage wave is determined, finding the highest reflected wave, adjusting the sensitivity gain to enable the height of the alarm wave to reach 80% of the height of the gate, carrying out online detection on the normally produced steel rail, comparing defects at the alarm position, and carrying out damage judgment recording. The method has the beneficial effects that transverse wave flaw detection is carried out on the rail bottom crack artificial defect of the steel rail, so that the internal quality of the steel rail is ensured, the sensitivity is higher, the detection is more accurate, the interference of rolling scars and pits at the rail bottom of the steel rail is avoided, and the requirement on the surface of the steel rail before detection is reduced.

Description

technical field [0001] The invention relates to a method for detecting rail bottom cracks by ultrasonic flaw detection of steel rails, and belongs to the technical field of ultrasonic flaw detection methods for heavy rails. Background technique [0002] Heavy rail ultrasonic flaw detection process includes rail deburring→surface cleaning→dimensional flatness detection→surface quality detection→ultrasonic flaw detection→finishing and other processes. All the rail standards at home and abroad all require that the out-of-the-box rails must pass ultrasonic flaw detection before they leave the factory. In particular, the new special rail standard TB / T2344-2012 of my country's railway department requires the full-length ultrasonic flaw detection of rails one by one. [0003] A steel plant adopts the ultrasonic flaw detection equipment of Canada NDT Company. The external artificial defect rail bottom is a 45-degree inclined hole, and the externally designed probe is a water immersi...

AI Technical Summary

Problems solved by technology

Due to the difference between the Chinese iron standard and the American standard for the rail, the Chinese railway standard stipulates that the rail bottom area is detected as a crack in the center of the rail bottom, and the artificial defect of the sample rail is changed from a 45-degree inclined hole in the rail bottom to a groove in the center of the rail bottom (width 1mm\deep 1mm\length 100mm), the change of artificial defects leads to the detection method designed with the original equipment can not meet the requirements of TB\T-2344-2012

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