Keeping your fasteners in top working condition is important to maintaining their effectiveness. There are several reasons for coating fasteners. Listed below are the 4 primary reasons:
- To improve the appearance of the fastener
- To fight corrosion
- To reduce friction
- To reduce scatter in the amount of preload achieved for a given torque.
There are a variety of coatings and platings that can be used to prevent or delay corrosion in fasteners as well as enhance the physical appearance of the fastener. The following are some of the most common.
Zinc Electroplating: Zinc is by far the most common and economical type of plating used for steel fasteners. It is relatively inexpensive and can be applied in a broad range of thicknesses. The service life of zinc plating is a function of its thickness, exposure to conditions and post plating treatments such as top coats. The most common zinc thickness is 2 to 5 microns thick.
Mechanical Galvanizing: The major advantages of mechanical galvanizing is that the fasteners do not suffer the risk of hydrogen embrittlement because the process is carried out without the use of electricity as well as the lack of acid used in the preparation of the fastener. Mechanical galvanizing provides greater corrosion protection because of its thicker layers which can range from 8 to 20 microns. However, the thicker layers will cause gaging issues with smaller fasteners.
Zinc Nickel: This plating offers superior protection than zinc as well as being RoHS compliant. Thicknesses run between 5 to 10 microns which makes this a very good choice for smaller fasteners that require greater protection.
Deciding which would be most effective for you can be a little difficult. To learn more about fastener platings and coatings or to receive help in deciding which you should use, reach out to us at ProvenProductivity@bossard.com. We would love to help you out.
Fastener Platings & Coatings by Bossard