I have a project on an island seashore. It is in a very harsh environment where it is very hot, high humidity and corrosive.
I use SST 316 machined parts as fixing brackets for anodized Aluminum Pipes (in direct contact).
I observed some Brown Rust Spots at the SST surface.
I want to know the following:
1- Can we consider this as a serious corrosion case.
2- What is the machining effect on SST 316? Do we need to have a polished surface if the rough machined surface may catch more corrosion.
3- Do we need to use some insulation between Aluminum and SST to avoid any galvanic corrosion, keeping in mind that size of SST bracket is very small compared to Aluminum.
4- Will the Acid Pickling and Passivationon be a helpful treatment for future jobs or do we need another coating?
5- Can we consider a guarantee (corrosion free product) of 15 years for SST 316 for such application.