Spray rinse is garden hose.
Pickling removes the oxides with relative ease. The parts appear clean after both alkaline cleaning and pickling, yet smut still remains.
More insight, we also have electropolish in-house. I ran a fairly heavy ep and even that didn't completely remove the smut...
Ammonium bifluoride appears to be a common substitute for straight HF, I guess because the AB is a solid and subsequently easier to store, ship and handle.
The pickle bath never exceeds 120F and may sometimes be performed at room temperature. The samples which were sent for analysis were at...
I've been working on a problem with passivating 304 SS tubes for some number of weeks. I've combed through ASTM A967 and A380 several times. Our process, at face value, meets the specification. We use an alkaline cleaner (tripolyphosphate based), followed by 20% nitric acid & 1% ammonium...
