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Time: Jun-22-2018

1. The requirement of appearance quality
The inspection of the appearance of stainless steel screws is from the appearance, electroplating and so on.
Two, the inspection of the thickness of the screw of the screw
1, measuring method: used with vernier caliper, micrometer, gauge etc..
2. Magnetic method: the magnetic method is used to measure the thickness of the coating layer. It is a nondestructive measurement of the non magnetic coating on the magnetic substrate by the magnetic thickness gauge.
3, microscopic method: microscopic method called metallography, it is through the fastener solution, placed in the microscope with magnification eyepiece micrometer on the coating thickness measurement section.
4, time liquid flow method

Timekeeping of liquid flow method is used to make the solution dissolved in local streamer coating surface coating, coating dissolved according to the local time required to calculate the thickness of coatings. There are also the coating method, the anode dissolving Coulomb method and so on.
Three. Inspection of the adhesion strength of the screw coating
There are many methods to evaluate the adhesion of coating and matrix metal, which are usually the following.
1. Friction polishing test;
2, test file;
3, scratch method;
4, bending test;
5. Thermal shock test;
6. Extrusion method.
Four, inspection of corrosion resistance of stainless steel screw plating
Test method for coating corrosion are: atmospheric exposure test; neutral salt spray test (NSS test); salt spray test (ASS test), copper accelerated acetic acid salt spray test (CASS test); and the Corrodkote corrosion test (CORR test) and drip solution corrosion test; immersion tests, immersion corrosion test etc..