How To Detect The Thickness of Boiler Tubes?

Boiler tube thickness detection is a key link to ensure the safe operation of boilers and extend their service life. Different detection methods have their own characteristics. Choosing the right method can effectively find defects in pipes and ensure the accuracy and reliability of the detection results. The following is a detailed introduction to several commonly used detection methods.

Ultrasonic detection method

1. Principle

The ultrasonic generator emits high-frequency sound waves. The propagation speed and reflection characteristics of the sound waves in the pipe wall can be used to measure the thickness of the pipe wall.

2. Operation

The ultrasonic probe is attached to the surface of the pipe, the returned sound wave signal is measured, and the wall thickness is calculated based on the propagation time and speed of the sound wave in the pipe wall.

3. Advantages

Ultrasonic detection is non-destructive, fast and accurate, and is the preferred method for detecting the wall thickness of boiler tubes. For boiler tubes made of seamless steel pipe or carbon steel pipe, ultrasonic detection can quickly locate changes in wall thickness and effectively monitor the wear of the pipe.

Radiographic detection method

1. Principle

Using the principle of X-ray or gamma ray penetrating materials, the defects inside the pipeline, such as uneven wall thickness or cracks, are judged by imaging analysis of boiler tubes.

2. Operation

Use professional equipment to irradiate the boiler tubes and obtain imaging results. The wall thickness and internal defects are judged by analyzing the imaging results.

3. Precautions

The radiographic detection method requires professional equipment and trained personnel to operate. At the same time, attention should be paid to radiation protection.

Magnetic particle detection method

1. Principle

Applicable to surface and near-surface defect detection of ferromagnetic materials. The magnetic powder is gathered at the defect through the magnetic field, so as to visualize the defect location.

2. Operation

Spread the magnetic powder on the surface of the pipeline, and then gather the magnetic powder at the defect through the magnetic field. Observe the distribution of the magnetic powder to judge the defect location and the uniformity of the wall thickness.

3. Limitations

The magnetic particle detection method is mainly used to detect surface defects such as cracks. It has limited direct effect on wall thickness measurement, but it can indirectly judge the uniformity of wall thickness. During the inspection process, for some boiler tubes with coatings or accessories (such as valves) on the surface, surface treatment may be required first to ensure that the magnetic powder can be effectively adsorbed at the defects.

Eddy current detection method

1. Principle

Suitable for surface detection of conductive materials. The thickness change of the material can be measured by the eddy current effect.

2. Operation

The eddy current detection probe is attached to the surface of the pipe and the pipe wall thickness is measured by the eddy current effect.

3. Features

The eddy current detection method works better in the case of multi-layer pipes or coatings, but attention should be paid to the selection and calibration of the probe. For some boiler tubes with insulation or protective coatings, eddy current detection can measure the wall thickness without destroying the coating, but the appropriate probe should be selected according to the specific pipe material (such as mild steel tube) and coating characteristics.

Manual measurement method

1. Tools

Use measuring tools such as calipers and micrometers for direct physical measurement.

2. Operation

For small-scale inspections or measurements at special locations, manual measurement methods can be used for direct measurement.

3. Limitations

The manual measurement method is suitable for special situations where the pipeline is not easy to operate, but the measurement accuracy and efficiency are relatively low.

Notes

1. Choose the right method

When measuring the boiler tube wall, it is necessary to choose a suitable measurement method to ensure the accuracy of the measurement. For different tube wall thicknesses, the corresponding measuring instrument should be selected for measurement.

2. Equipment calibration

When using high-precision equipment such as ultrasonic measuring instruments, it is necessary to calibrate in advance to ensure the accuracy of the measurement results.

3. Comply with standards

During the inspection, relevant standards and regulations should be followed to ensure the reliability and effectiveness of the inspection results.

4. Multi-method integration

When necessary, multiple inspection methods are used to complement each other to improve the comprehensiveness and reliability of the inspection.

Summary

In summary, the ultrasonic inspection method is usually the preferred method for boiler tube wall thickness inspection due to its non-destructive, fast and accurate characteristics. Other methods such as radiographic inspection, magnetic particle inspection, eddy current inspection and manual measurement can be used as auxiliary inspection methods to improve the comprehensiveness and reliability of the inspection.