Aloha, fun & authoritative answers -- no cost, no registration, no passwords, no popups
(as an eBay Partner & Amazon Affiliate we earn from qualifying purchases)

Where the
world gathers for metal finishing
Q&As since 1989

-----

Pitting corrosion of SS304

We are recently facing a pitting corrosion problem on the surface of SS304. the steel tubes are filled with MgO powder and than heated. the outer surface of the tubes contain coffee colored amorphous powder (confirmed by XRD). SEM images shows pitting corroded surface. What could corrode it? Is it the chlorides in tap water or any pre treatment or manufacturing defect of steel?

Narendra Chauhan
IPR - Gamdhinagar, Gujarat, India
2003

Your question is probably clear in your own mind, Mr. Chauhan, but I have very little understanding of what you are trying to describe. These tubes are going into an oven to do something to the MgO that is within the tubes? What temperature do they see? What atmosphere? You periodically rinse them and are concerned about residues from the rinsing causing the corrosion? I don't understand what the XRD confirmed--certainly something different than that the residue was coffee-colored. Please try to explain the situation more fully. Thanks!

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003

(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: