The authoritative public forum
  for Metal Finishing since 1989
-----

Stainless steel contamination

 

There are any intructions or documents which give intructions to how conserve stainless steel surfaces to avoid contamination (e.g. rust, conctact with c.s. products, dedicated tools, etc.).

Danilo Moro
- Buttrio, Udine, Italy

---

Danilo:

Best way to avoid rust and contamination of SS from the standpoint of the metal surface itself, is to pickle it before use by immersion in 30% nitric, 6% hydrofluoric, rest water. Then passivate it in 30% nitric acid and water (no hydrofluoric), then neutralize it for use. If contamination has occurred the nitric mix described for passivation will eliminate most of it, if it is ferrous. Neutralization of the acid is nessesary for re-use. Good luck.

Guillermo Marrufo
Monterrey, NL, Mexico

---

 

Danilo:

Refer to ASTM A967-99. You can do the job simplest and safest with citric acid formulae available on the market.

Lee Kremer
Stellar Solutions, Inc.

McHenry, Illinois