There are two kinds of surface inspection of screws, one is the inspection before the electroplating process after the production of screws and the other is the inspection after the electroplating process of screws.Please inform us the inspection method after the screw is settled:

1. Specification of appearance quality: the inspection of screw appearance is carried out at various levels such as appearance and electroplating.

2. Inspection of the thin and thick coating of screws: test by measuring instrument method, magnetic method, optical microscope method, countdown flow method, etc.

3. Inspection of adhesive compressive strength of screw coating: friction, grinding and polishing test;Tool test;Scratch method;Bending test;Thermal shock test;Extrusion molding.

4. Inspection of corrosion resistance of screw coating: air exposure test;Neutral salt spray test (NSS test);Glacial acetate fog test (ASS test), copper accelerated glacial acetate fog test (CASS test);Its corrosion paste corrosion test (CORR test) and aqueous solution point

5. Drop corrosion test;Prepreg test, interdip corrosion test and so on.