Tungsten tubes, characterized by their high melting point, high strength, corrosion resistance, and low thermal expansion coefficient, are widely used in high-temperature furnace tubes, semiconductors, aerospace, vacuum devices, and other fields. The core objective of polishing tungsten tubes is to remove oxide scales, tool marks, and drawing marks, and to enhance the inner/outer wall smoothness, roundness, and dimensional accuracy, while maintaining the properties of the tungsten substrate.

       1. Common polishing processes for tungsten tubes

       1. Mechanical polishing (external cylindrical polishing)

       It is suitable for the finishing of the outer surface of tungsten tubes and is a commonly used industrial polishing method.

       Process: rough grinding → medium grinding → fine polishing

       Abrasives: diamond grinding wheel, diamond abrasive paste, thousand-leaf wheel, non-woven wheel

Features:

       High efficiency and strong controllability

       It can achieve a mirror effect

       Suitable for long tubes and thick-walled tungsten tubes

       Achievable surface finish: Ra 0.2～0.05 μm

       2. Inner hole polishing (inner wall polishing)

       Due to the limited space on the inner wall of the tungsten tube, flexible honing and abrasive flow polishing are generally employed.

       Abrasive Flow Machining (AFM):

       Utilize viscoelastic abrasives to flow back and forth through the inner hole under pressure

       Evenly remove burrs, oxide layers, and drawing lines

       Ensure the coaxiality and roundness of the inner wall

       Suitable for: tungsten tubes with fine diameter and large aspect ratio

       Achievable surface finish: Ra 0.1～0.05 μm

       3. Electropolishing (electrochemical polishing)

       Suitable for tungsten tubes with high precision and high cleanliness requirements.

       Principle: Through electrochemical dissolution, the microscopic protrusions on the tungsten surface are preferentially dissolved

Advantage:

       No mechanical stress, no deformation

       The surface is uniform and free from work-hardened layer

       High cleanliness, suitable for semiconductor/vacuum industry

       Achievable surface finish: Ra ≤ 0.05 μm (mirror-like finish)

       4. Chemical polishing

       Used for light finishing and descaling of tungsten tubes.

       Using a strong oxidizing acid solution system, gently corrode the surface

       Suitable for thin-walled, irregularly shaped, and tungsten components that cannot be mechanically polished

       Characteristics: fast speed, low cost, but slightly lower accuracy

       II. Key points of tungsten tube polishing

control temperature

       Tungsten has high hardness and poor thermal conductivity, so it must be fully cooled during polishing to avoid local overheating, oxidation, and embrittlement.

       Avoid stress and deformation

       For thin-walled tungsten tubes, electrolytic/abrasive flow polishing is preferred to minimize mechanical force.

       Cleaning treatment

       After polishing, ultrasonic cleaning, drying, and vacuum packaging must be carried out to prevent surface re-oxidation.

       Dimensional accuracy control

       The polishing allowance is generally controlled between 0.02 and 0.1 mm to ensure the outer diameter/inner diameter tolerance.