M2 stainless steel countersunk head dacromet coated machine screw

Industry knowledge：

Why is the coating of stainless steel screw easy to fall off?

Generally speaking, stainless steel screws rarely do surface treatment, and most of them are primary colors. However, some will do surface treatment in order to increase the beauty of appearance, some to increase corrosion resistance and rust resistance, and some will also do surface treatment. Some of the coating surface is easy to fall off. How to solve this?
Stainless steel screws are easy to fall off only when doing the surface treatment of environmental protection black zinc coating. This is because the adhesion between stainless steel and electroplating solution is not very strong, so they will fall off easily. If the customer only wants a black surface, it can be oxidized and blackened. If it is to increase the anti rust performance of screws, it can be changed to passivation, zinc nickel alloy and other surface treatment.