Tungsten Copper Contact —Ultrasonic NDT

Tungsten copper contact is also known as tungsten copper electrical contact or tungsten copper contact tip, which is a kind of psudoalloy that consist of W and Cu two kinds metals of immiscible and without the formation of intermetallic compounds. Consequently, it not only has high hardness, high melting point, high strength, low coefficient of thermal expansion and excellent wear resistance and corrosion resistance of W, but also has perfect electrical and thermal conductivity and plasticity of Cu. And it has been played an important role in some high-voltage switch, breaker, and instrument components.

Currently, preparation of tungsten copper contacts is mainly used in PM (powder metallurgy) technology, the corresponding method used for the performance testing, such as the density, the hardness, the compressive strength, the tensile strength and micro-structure, etc., will have some damages on the integrity of tungsten copper products and lead to failure. And these tools to test for products in large quantities can only do a certain proportion of sample, which is difficult to have some representation. If the unqualified tungsten copper contacts undetected used in actual production is likely buried security risk, both for production or personal safety is extremely unfavorable. So the relevant researchers use Non-destructive testing techniques to measure and evaluate the mechanical properties of tungsten copper related products.

Ultrasonic NDT (Non-destructive Testing) is a kind of process that ultrasound can penetrate deep into the use of a metallic material, by entering a cross-sectional another cross-sectional; edge reflection occurs at the interface characteristics of the parts to check for defects. When the ultrasonic beam from the surface of the part by the probe pass to the metal inside encounter defects and Part underside of the reflected wave occurs, respectively, form a pulse waveform on the screen, based on these pulse waveforms to determine the location and size of the defect. Compared with other detecting methods, Ultrasonic NDT has many advantages, such as:

1. Ultrasound has perfect penetration ability, low transmission loss and the probing depth of up to several meters;
2. High sensitivity, it can be found with the diameter of the air-based reflectance 0.1-1mm equivalent reflector;
3. Accurate positioning, to assume the shape and the size are also more accurate;
4. Convenient in operation and it is suitable for the most materials;
5. The entire testing process will not cause environmental pollution, no harm to the human body completely.

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