Non-destructive Testing Methods for Steel Pipes

At present, there are many types of steel pipes in the market, and the application range is also different. For example, seamless steel pipes have high strength and good corrosion resistance, and are applied in many aspects such as piping systems and machinery industries.

In order to meet the market demand, there is a high requirement for the quality inspection of steel pipes. The structure, state and performance of the inner or surface of the steel pipe are inspected by means of non-destructive testing to determine whether the steel pipe is qualified.

This test does not damage the steel pipe to be tested. Performed under the conditions of the internal structure.

1. Ultrasonic testing is based on the principle of electromagnetic effect. When ultrasonic waves are excited in the tube, the beam will be reflected and attenuated when the surface defects of the tube are encountered during the propagation.

After the information is processed by the flaw detector, the instrument will give The defect shows that cracks, straight defects and non-metallic inclusions in the steel pipe can be detected, and the detection sensitivity is relatively high.

However, the detection speed is relatively slow, and it is suitable for off-line inspection of high quality steel pipes.

2. Eddy current flaw detection, this summary method will cause the detection end zone of 200mm length around the tube end, which is caused by the limitation of the detection method.

The eddy current testing equipment has two kinds of probes and through-type probes.

During the detection process, the point probes are moving forward in a spiral manner. The inspection time is relatively small, the efficiency is low, and the penetrating probe device is talkative and the detection speed is fast.

It can detect defects such as cracks, concave surfaces and crusting on the surface of steel pipes, and has high sensitivity. It is one of the commonly used methods for steel pipe inspection.

3. Magnetic flux leakage detection is the leakage magnetic field generated when the steel pipe to be inspected is magnetised, and the defects appear on the surface of the pipe. The defects of the steel pipe are found by magnetic flux leakage detection.

Magnetic flux leakage testing is mainly carried out by magnetic field measurement and magnetic particle inspection. It can realize automatic flaw detection and is suitable for automatic detection of a large number of steel pipes.

Magnetic particle inspection facilitates the detection of the inner and outer surfaces of steel pipes, and is sensitive to the detection of cracks, folds, hair lines, pinholes and other defects on the surface of steel pipes.

All of the above are conventional methods for steel pipe inspection, but each method can only detect certain defects and cannot detect all defects. Therefore, some manufacturers combine the through-type eddy current testing and magnetic flux leakage testing. It can effectively detect the main defects in the steel pipe.

At present, the level of steel pipe inspection technology is getting higher and higher, which guarantees the quality of steel pipes, so that people use steel pipes more reassuringly. More info refers to:

Source: OilVoice