Eddy Current Testing Machine is Widely Used

Eddy Current Testing Machine is Widely Used

Ⅰ. About eddy current testing machine

The eddy current testing machine has a compact structure, small size, and lightweight. It promotes the eddy current flaw detection method to general industrial field applications at a low price, so the instrument is very suitable for industrial field flow detection, such as aviation, aerospace, machinery, metallurgy, electric power, petrochemical, and other departments production and research.

It is specially used to detect the weld quality of various straight seam welded non-ferromagnetic pipes (such as copper, aluminum, austenitic stainless steel, etc.). It can also detect ferromagnetic pipes (such as steel pipes, etc.) with a magnetic saturation device. With different types of probes (such as external penetration, flat and saddle probes), online or offline rapid ect NDT of round tubes, square tubes, or other pipes with various cross-sectional shapes can be performed.

Ⅱ. Comprehensive application analysis of eddy current testing machine

1. Workpieces requiring simultaneous magnetic particle (wet) inspection and penetrant inspection

Penetrant testing should be performed first, and then magnetic particle (wet) testing.

The wet magnetic powder detected by the magnetic particle (wet) is also dirty. Under the action of a strong magnetic field, the wet magnetic powder will be tightly adsorbed on the opening defect. Even after demagnetization with a strong magnetic field, wet magnetic powder residues are still difficult to remove. If magnetic particle (wet) testing is performed first and then penetrant testing, different cleaning methods should be used depending on the magnetic suspension.

2. Workpieces requiring simultaneous ultrasonic testing and penetrant testing

Eddy current testing machine should perform penetrant testing first and then ultrasonic testing.

Liquid couplants used in ultrasonic testing are also contaminants and can clog or fill open defects. Liquid coupling soils are also difficult to remove. If penetrant testing is performed after ultrasonic testing, different removal methods should be used depending on the liquid couplant.

3. Penetration testing of in-service workpieces

First, the workpiece needs to be disassembled from the in-service equipment. If there is paint on the surface of the workpiece, it must be removed. In addition, the scale, rust, and corrosion products on the surface of the workpiece can be treated by acid etching (commonly used) or alkali cleaning.

After acid etching or alkali cleaning, the in-service workpiece must be thoroughly rinsed. Otherwise, the acid or alkali residue may affect the performance of the penetrant.

4. Penetration detection of aircraft workpieces by eddy current testing machine during overhaul

Many workpieces on the aircraft are light metals such as aluminum alloys, titanium alloys, and copper alloys, which are all non-ferromagnetic materials. Although some workpieces are ferromagnetic materials, they are often not suitable for magnetic particle testing due to geometrical shape and size limitations. During major repairs, these workpieces require penetration testing.

For penetrant testing of such in-service workpieces, they must be disassembled from the aircraft as a whole. Then they must be cleaned with solvent or alkali or acid etching to remove contaminants such as lubricating oil, scaling, and corrosion products.

Local areas with severe scaling and corrosion products can be cleaned with stainless steel wire brushes. Small areas that may have open defects can be cleaned by hand sanding.

5. Penetration testing of heat-resistant and corrosion-resistant alloy workpieces during overhaul

Many heat-resistant and corrosion-resistant alloy workpieces (mostly non-ferromagnetic materials or weak magnetic materials) are used in high-temperature and strong corrosive environments, so complex oxide deposits are formed on the surface. They bond very well to the workpiece surface and often form thick scales etc. During major repairs, these oxide deposits can be removed by an industrial salt bath method.

The eddy current testing machine is designed with advanced impedance plane technology and has high detection sensitivity for defects such as unfused welding, dark seams, open cracks, pores, slag inclusions, and folding in the production process. The instrument can timely alarm for pipe defects or production failures, remind the operator to pay attention, and control the actuator to deal with it, to avoid product scrap and improve product quality. The instrument conforms to international general eddy current flaw detection standards such as GB, DIN, ASTM, API, and BS.

  • 3-102,No.1 Hengyi Road,Qixia District, Nanjing City, Jiangsu Province, China.
    3-102,No.1 Hengyi Road,Qixia District, Nanjing City, Jiangsu Province, China.
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