Can you comeback with the process you use to produce the fastener as well as the secondary operations like the passivation, etc. Need to know concentration times and t4 temperature of the secondary operations.
Hi unclesyd
about the process for the fasteners Im not sure (Ill find out and get back to you) about the passivation it was per ASTM 967 Nitric I
(what is t4 temp?)
15-5 is easily passivated and as posted above there is probably something amiss in the procedure. either in pickling or passivisation.
If you are pickling it the time, temperature, and concentration could wrong. The passivisation step is also open to problems especially if your pickling step is excessive. As in pickling, time, temperature, and concentration are important.
Awaiting your response.