Rail Surface Defects Detection

What are rail surface defects?

Rail Surface Defects

Rail surface defects are mainly divided into two types: surface cracks and rolling contact fatigue wear.

Rails have higher steel requirements than any other application. The same small flaws may not cause any problems if they appear in the steel bars used in buildings, but if they appear in the railway rails, they can cause the rails to break at any time and cause the train to derail. There are two main forms of fatigue wear, including rail head block drop and rail head corrugation wear. Fatigue wear on the rail surface not only affects the accuracy of ultrasonic flaw detection technology but also the wear at some special locations, such as the wear around the measuring angle of the rail head, which may also develop downward into a more dangerous internal nuclear injury.

The operation of high-speed and heavy-haul railways places stringent demands on the reliability of railway infrastructure. As part of infrastructure inspection work, rail flaw detection plays a vital role in the safety of railway operations. In the past, most online rail fractures were caused by internal defects. Internal defects usually occur at the waist and head of the rail. With the excessive wear and fatigue use of the rail, the internal defects continue to develop and expand, eventually leading to rail breakage accidents. Now with the introduction of advanced production technology, such as high-carbon steel and iron and steel cleaning production processes, the probability of internal defects of the rail has been reduced a lot, and the surface defects of the rail that lead to the fracture of the rail is becoming more and more common.

The surface defect of the rail is an important factor affecting the quality of the rail. Therefore, the surface of the rail needs to be strictly inspected before the rail leaves the factory. At present, the main method of surface inspection of the rail in the production process is manual visual inspection, which has low efficiency and labor intensity. Problems such as large size and seriously missed inspections have become the “bottleneck” of rail production. The surface defect online detection technology can solve the problems existing in the manual visual inspection method. The profile measuring instrument is an instrument for online surface defect detection based on the laser principle.

Rail surface defects detection method

1. Two-dimensional laser measurement sensor

Measured using laser triangulation. During measurement, the sensor emits a line of laser light to illuminate the surface of the object to be measured, and the camera system in the sensor captures the image of the linear light spot on the surface of the object to be measured. By analyzing the position of the light spot on the CCD or CMOS chip of the camera system, the coordinates of the X-axis and Z-axis of the linear light spot can be obtained.

2. using four sensors

One two-dimensional laser measurement sensor measures the contour size in one direction, and four sensors can cover the entire section to complete the comprehensive inspection.

3. Detection frequency

The detection frequency of each sensor is 4000Hz, and they detect at the same time and cooperate with each other. The detection speed is fast, which can detect the full size and reduce the impact of rolling material jitter.

4. Complete surface

The profiler detects one section shape after another, and at the same time, the detection speed is fast, and the complete surface can be displayed in high resolution through software calculation and simulation. Thereby local and periodic surface defects are detected.

The profiler is applied to the detection of surface defects of rails.

The online automated detection method upgrades the production mode to obtain high-quality rails with high efficiency.

Choosing the high-quality steel rails can minimize the risk for these problems. Contact us for more high-quality steel rails for your subject!