Such as special-shaped screws, non-standard screws and so on. After testing, it will find out the unqualified parts of the product, and then improve your product better. only in this way can we provide customers with better products and win the favor of users.
Testing, appearance and quality requirements of non-standard screws in fasteners; appearance inspection and plating inspection of non-standard screws. The thickness of the screw coating can be inspected with a micrometer, vernier caliper, plug gauge, etc. The magnetic method measures the thickness of the coating layer. It is a non-destructive measurement of the non-magnetic coating layer on the magnetic substrate with a magnetic thickness gauge. The microscope method is called metallographic method. Magnify on a metallographic microscope with a micrometer eyepiece to measure the thickness of the coating on the cross section; timed flow method.
The timed flow method is to inject a solution capable of dissolving the plating layer on the local surface of the plating layer, and calculate the thickness of the plating layer according to the time required for the local plating layer to dissolve. There are also coating drip method, anodic dissolution coulomb method, and the like. Inspection of screw coating adhesion strength: There are many methods to evaluate the adhesion between the coating and the base metal, usually the following: friction polishing test; file method test; scratch method; bending test; thermal shock test; extrusion method. Corrosion resistance test of stainless steel screw plating: The corrosion resistance test methods of coating are: atmospheric exposure test; neutral salt spray test (NSS test); acetate salt spray test (ASS test), copper accelerated acetate salt spray test (CASS Test); and corrosion paste corrosion test (CORR test) and solution drip corrosion test; immersion test, inter-immersion corrosion test, and so on.