Surface defect detection of heat exchanger row weld - Application of ACFM technology in pressure vessel field

1 Inspection background:

Heat exchanger is the equipment that transfers part of the heat of the hot fluid to the cold fluid, also known as the heat exchanger. Heat exchangers are general equipment for chemical, petroleum, power, food and many other industrial sectors, and occupy an important position in production. The heat exchange pipe has been in the use of high temperature, high pressure, corrosion and other different environments, with the extension of the use of time, different degrees of corrosion, cracks and other defects may occur, so in service detection of heat exchange pipe has become an urgent need for many chemical enterprises.

2 Inspection status:

At present, the welding seam testing methods of heat exchange tubes are still mainly conventional testing, including penetration testing, magnetic particle testing and X-ray testing. However, due to the limitation of working space, penetration testing and magnetic particle testing can only be conducted on the upper half of the first row of heat exchange tubes. And the pipeline needs to be polished in advance, time-consuming and laborious. X-ray inspection can be complete, but the inspection cost is high, and there are security risks.

3 Test method:

Ac electromagnetic field detection (ACFM) is a non-contact nondestructive detection method for surface or near-surface defects based on the principle of electromagnetic induction. Stable inspection of small tube butt welds can be achieved by making wedge pairs suitable for different pipe diameters, and pen probes can be passed through the row space to inspect all pipes without fear of missing inspections.

4 Technical advantages:

1. The wedge can be customized according to the pipe diameter to realize the full detection of the platoon weld, avoiding the shortcomings of limited working space of magnetic particle and penetration detection;

2, suitable for carbon steel, stainless steel, aluminum alloy and other materials, to solve the problem that magnetic particle detection can not detect dissimilar steel butt weld;

3, no pollution to the environment and human body, to avoid the safety problems of X-ray detection. Immediate output results, improve the inspection efficiency.

5 Typical applications:

1. Test the fatigue crack of the butt weld of the heat exchanger row pipe;

2, dissimilar steel butt pipe weld surface defects detection.