Zinc rich epoxy primer on SS substrate?? 2

[bmoorthy]

One of our suppliers painted SS material with the following paint

Zinc Rich Epoxy + Epoxy MIO high Built + Polyurethane.

This happened becuuse SS parts constitutes (By value) less than 10 % of the order value (Seal piping system for Pumps).

By area SS constitutes around 25 % as against CS that constitutes 75%.

What are the consequences of applying zinc based primer on SS substrate?

Is it prohibited to use Zinc rich epoxy on SS Substrate

ISO 122994 does not provide guidelines for selection of paints on SS Substrate, are there standards (Codes, Specification or International standards) that deal with painting SS substrate?

 

[gr2vessels]

bmorthy,
The topic of zinc painting of the stainless steel (austenitic) was exhaustively discussed many times on this forum;- try the search feature in top of this page.
However, the application plays a huge role in defining the interaction between zinc and stainless steel. It all depends.
A SS pressure vessel primed with zinc containing paint, subjected to internal or external overheating could crack (at worst) within minutes. It will take however, 1000 years to break down the stainless steel rabbit fence painted with zinc primer.
I have not allowed ever to paint stainless steel with zinc containing paint in pressure systems, oil and gas, as matter of principle (you never know, Murphy's law). On the other hand, I have specified TSA coating with 5% zinc and then a Teflon top coat, for a relative low temperature Duplex heat exchanger on a FPSO, apparently it will last donkeys ears. True, it will not see any fire, the FPSO will sink before the fire will reach to the exchanger...
cheers,
gr2vessels