No registration or passwords; no pop-up ads -- just aloha, fun, & answers.
(as an eBay Partner & Amazon Affiliate earns from qualifying purchases).
Home /
T.O.C.
Fun
FAQs
Good
Books
Ref.
Libr.
Advertise
 
Help
Wanted
Current
Q&A's
Site 🔍
Search
pub  Where the
world gathers for metal finishing
Q&As since 1989



-----

Passivation of EXTERNAL surface of air cooler fin-tubes after cleaning





Q. Dear all,

I'm Joko Lelono, Process Engineer working in a refinery.

We are planning to carry out the chemical cleaning on the external surface of our air fin coolers. The tube materials are constructed from carbon steel while the fins are aluminium, embedded type.

Considering the main dirt is rust /scale on the carbon steel bars and not dust in the fins pitch, we decide to carry out the acid pickling to clean out this scale / rust. We'll use inhibted H3PO4 for pickling, then after rinsing we are going to passivate the tube external surface using NaNO2.

Please advise whether such planning is acceptable or not? I'm reviewing the literature, and so far I can only find that chemical cleaning sequence from degreasing--rinsing--acid pickling--rinsing--passivation is applied only for internal part of tubes / pipes --while for external surface I wonder whether such sequence is still applicable.

Thanks for the responses.

Joko Lelono
- Tuban, East Java, Indonesia
March 26, 2012




(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

 
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g, Train'g
& Software


About/Contact  -  Privacy Policy  -  ©1995-2024 finishing.com, Pine Beach, New Jersey, USA  -  about "affil links"