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


-----

Removing Welding Stain from SS 316 Boxes

I would like to know the best method of removing welding (TIG) stains from SS 316 boxes. I used K2 Paste, but the results are not so appreciable. Is it advisable to use a little caustic soda [affil links] ? I look for a solution for the above process. Also how can I polish the corners where the buffing wheels cannot reach?

Mahesh [last name deleted for privacy by Editor]
contractors - India
2006

---

2006

Dear Mahesh,
Cleaning and Passivation of stainless steel has till recently been a method which utilizes mineral acids or its salts.There usage is limited to surface iron.This method re deposits surface iron very quickly that the surface starts looking rusty soon.
Stainless Steel is comprised of a mixture of primarily iron,Cr,Ni and other material blended uniquely to give special properties to SS.During welding, because of excess heat generated,the percentage of those mentioned above changes and more iron surface on the top layer giving a rusty look.
You may need some thing to first remove welding scales and rust and to then prevent the surface from re-deposition of removed free iron.
There are products now available to give the result you are looking for.One such company manufacturing these products are, Surtec International USA and I understand they have representation in India too.
Best of Luck.

T.K. Mohan
plating process supplier - Mumbai, India

You can use jelly for your weld seam cleaning purpose. It will not give further rusting problem as told above.

Vinay Golwala
- Mumbai ( Bombay ), India
2007