Why does aluminum socket head cap screws have spot on the surface?

Screws are used in many industries, such as electronics, machinery, manufacturing and so on.And a lot of screw fasteners will also be electroplated or other processing, mainly in order to enhance the screw performance. Aluminum screw surface can do a lot of color, basically as long as the color plate, you can make according to the color plate. But why are there spots on the surface of aluminum socket head cap screws?

The spot on the surface of aluminum socket head cap screws is mainly caused by salt spray test. The aluminum hexagon cup head screws tested by salt spray will have a layer of oxidation spots on the surface, so it looks like there are spots on the surface.

Generally, when customers say that they want to do salt spray test on aluminum socket head cap screws, we will tell them that there will be a layer of oxidation spot on the surface of aluminum screws, and ask them whether they can accept such a surface. If the customer can accept, then we will do a salt spray test for the customer.

If you want to customized aluminum socket head cap screws please email: annie.li@szsst88.com