Finish

Plain

Nothing has been done to this bare metal surface to improve appearance or corrosion resistance, which is very low if the material is steel. Often the surface has been oiled which improves lubricity. This finish is susceptible to rusting and corrosion in exterior environments. This most basic finish can be used when protection is not an issue or indoors.

Zinc

This finish, also know as zinc plating, zinc chromate or dichromate provides good corrosion resistance and is the standard for many hardware fasteners. It is an electroplated zinc layer covered with a chromate post-treatment. The zinc protects the steel from corrosion and the chromate layer protects the zinc from degrading. It is a popular finish because of its protection, value, and ease of coating. Slightly less corrosion resistant than yellow zinc, it is a versatile finish that is best used indoors. This finish should not be used in marine or high salt spray environments.

Material

Steel

Steel is the most common fastener material due to its strength properties. Unalloyed steel may be surface treated to enhance corrosion resistance and other desirable properties.