High temperature steam pipeline valve surface defect detection - Application of ACFM technology in the field of electric power

1 Inspection background:

The steam pipeline of the power station is in high temperature and high pressure environment for a long time, which is easy to produce creep cracks and lead to destructive accidents, which directly affects the safe operation of the boiler and the normal operation of the whole thermal power generation system. In order to ensure the safety and continuity of production operations and prevent accidents, it is becoming more and more important to study the convenient, efficient and high-precision high temperature pipeline defect technology.

2 Inspection status:

The existing detection methods are usually magnetic powder and penetration detection, ordinary magnetic powder or penetration can not be carried out at high temperature, and the pipeline surface needs to be polished, paint and rust removal before the inspection. High temperature magnetic powder is detected by dry powder method, but the detection accuracy of dry powder method is usually worse than that of wet method. Eddy current testing has also begun to be applied in high-temperature pipeline testing, but the detection depth of eddy current testing is only 1-2mm, and there is a problem of deformation and damage of the probe at high temperature.

3 Test method:

Ac electromagnetic field detection (ACFM) technology is based on the principle of electromagnetic induction of structural surface or near surface defects non-contact non-destructive detection method, because the electromagnetic properties of materials are less affected by temperature, theoretically can achieve high temperature detection. Through the design and manufacture of high temperature probe and connecting wire, the high temperature detection below 350℃ is realized. At the same time, by reducing the flow rate and other measures, the pipeline temperature is temporarily reduced, so as to realize the continuous inspection of pipelines and valves.

4 Technical advantages:

1, can be tested at 350℃ high temperature, higher temperature resistance than high temperature magnetic powder and penetration technology, more applicable scenarios;

2. It is not necessary to remove the paint layer of the pipe surface during testing, avoid the grinding work required by ordinary magnetic powder and penetration testing, and improve the detection efficiency;

3, no consumables, cost savings;

4, the test process data is stored in the equipment, can be recorded, traceable, easy to information management.

5 Typical applications:

1, power plant steam pipeline boiler pipeline defect detection;

2, pharmaceutical reactor surface defect detection.