A. Appearance quality requirements
The appearance inspection of stainless steel screws is carried out from the aspects of appearance, electroplating and so on.
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B. Check the screw coating thickness
1. Method of measuring tools for titanium screws: use micrometers, vernier calipers, plug gauges, etc.
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2. Magnetic method: The thickness of the coating is measured by the magnetic method, which is a non-destructive measurement of non-magnetic coatings on magnetic substrates using a magnetic thickness gauge.​​

3. Microscopy: Microscopy is called metallographic method, which is to unfold the etched fasteners on the metallographic microscope with a micrometer eyepiece, and measure the coating thickness of this part.

4. Timed liquid flow mode
The timed liquid flow method uses a solution that dissolves the paint poured onto a portion of the surface of the paint and calculates the thickness of the paint based on the time it takes to dissolve a portion of the paint. There are also drop coating method, anodic dissolution Coulomb method, etc.
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C. Inspection of Screw Coating Adhesion
There are generally several ways to evaluate the adhesion between a coating and the base metal.
1. Conflict polishing experiment;
2. Document method experiment;
3. Scratch method;
4. Zigzag experiment;
5. Thermal shock test;
6. Knead.

D. Corrosion Resistance Inspection of Stainless Steel Screw Coatings
Coating corrosion resistance inspection methods include: atmospheric exposure test; neutral salt spray test (NSS test); acetate spray test (ASS test), copper accelerated acetate spray test (CASS test); corrosion paste corrosion test ( CORR test) and solution drop corrosion test; immersion test, interphase corrosion test, etc.