There are two types of screw surface inspections, one is the inspection before the screw is produced, and the other is the inspection after the screw plating.
Inspection method after screw treatment:
Appearance quality requirements: The inspection of the appearance of the screws is carried out in terms of appearance, plating and other aspects.
Inspection of the thickness of the screw plating: using the gage method, magnetic method, microscopic method, timed flow method, etc.
Inspection of adhesion strength of screw coating: friction polishing test; boring method test; scratch method; bending test; thermal shock test; extrusion method.
Corrosion resistance test of screw coating: method includes atmospheric explosion test; neutral salt spray test (NSS test); acetate spray test (ASS test), copper accelerated acetate spray test (CASS test); and corrosion corrosion of corrosive paste Test (CORR test) and solution drip corrosion test; immersion test, inter-dip corrosion test and so on.
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