Surface Finish options are numerous; however, there is always an optimum selection among alternatives based on the Fastener Functionality, Material, Type, Configuration, Mating Part Material, Design Requirements, Environment, etc.
Surface Finishes are specified to provide higher Corrosion Resistance or a specific colour to suit the assembly, yet the selection should be made based on other important considerations such as Galvanic Corrosion.
For example, when the protective zinc coating of galvanized steel sheets is broken and the underlying steel is attacked, the zinc corrodes preferentially because it is less noble. However, once the zinc coating has been consumed, serious rusting of the base metal can occur.
Stress Corrosion Cracking (SCC) is the growth of cracks of certain alloys in a corrosive environment, which can also lead to catastrophic failures. Special attention must be made to study the environment vis-à-vis and the bolted joint components. This requires comprehensive knowledge, experience, and techniques to avoid such failures.
At Vine Engineering, we have an intensive experience in specifying the optimum Surface Finish solutions for your application.