Requirements for special screw maintenance layer: corrosion resistance, wear resistance, high hardness,the structure is tight, intact, and the pores are small. Corrosion is formed in the medium of stainless steel standard parts.Special screws are made of metal, and there are four main methods for metal corrosion prevention, namely the nature of the material itself, the environment in which it is used, the interface between the material and the environment, and the design of improving the metal structure.

Non-metallic coating refers to the use of organic polymer materials such as paint and inorganic materials such as ceramics to form a maintenance layer on the surface of metal equipment or parts. Measuring tool method: the amount used includes micrometer, vernier caliper, plug gauge, etc. Microscopy: The microscopy method is called the metallographic method, which is to magnify the etched fasteners on a metallographic microscope with a micrometer eyepiece to measure the thickness of the coating on the section. Third, the inspection of the adhesion strength of Wholesale Concrete Screw the screw coating

There are many ways to evaluate the adhesion of the coating to the base metal, and there are usually the following. Fourth, the corrosion resistance inspection of non-standard screw plating The coating corrosion test methods include: atmospheric exposure test; neutral salt spray test (NSS test); acetic acid salt spray test (ASS test), copper accelerated acetic acid salt spray test (CASS test); and corrosion paste corrosion test (CORR test) and solution spot corrosion test; immersion test, inter-immersion corrosion test and so on.

Timing sap flow method The chronograph flow method is to use a solution that can dissolve the coating on the partial surface of the coating, and calculate the thickness of the coating according to the time required for the partial coating to dissolve. Second, the inspection of the thickness of the screw coating.

Magnetic method: The magnetic method measures the thickness of the coating layer, which is a non-destructive measurement of the non-magnetic coating layer on the magnetic substrate with a magnetic thickness gauge. Thermal shock test; The appearance inspection of non-standard screws is carried out from the appearance, plating layer and other aspects. There are also plating spot method, anode dissolution coulometric method and so on.