Why Is The 2mm Socket Head Cap Screws Grey After Phosphating, Not Black?

The 2mm socket head cap screws that is currently produced is generally surface treated. Some are for a beautiful look, and some are for a certain feature. But the surface-treated screws are sometimes a little different from what we want, like phosphating. Some phosphating treatments are gray, not black. Why is this?

The  2mm socket head cap screws are made of carbon steel and need to be phosphate. The hardening and heat treatment is carried out after the screw head and the tooth decay, and the surface color of the heat-treated  2mm socket head cap screws is black. Without heat treatment, the screws that are directly phosphatized and phosphatized, the surface color is gray. The difference between these two colors is worse than the heat treatment process.

Therefore, in order to prevent the appearance that the customer wants is not the same, we will confirm with the customer what the required surface color is. Thereby to determine whether heat treatment is to be performed.

If you want to customize  2mm socket head cap screws, please send an email: annie.li@szsst88.com