finishing.com -- The Home Page of the Finishing Industry
A website for Serious Education, promoting Aloha,
& the most FUN smiley you can have in metal finishing

HomeFAQsSuggested
Books
Help
Wanteds
Advertise
Here
FORUM
(current
topics)
topic 8506

Removing Scale from Stainless Steel


(2001)

I am looking for a pickling solution to clean up the scale from stainless steel. I already tried Nitric acid, Hydrochloride acid. But it doesn't remove all the scale. I also know the Hydrofluoric acid can do the job, but because this chemical is too toxic and corrosive, so my company will not allow me to use it. If anyone knows any better ways or any other pickling solution, please let me know.

Thank you very much.

Albert Tsang
- England, U.K.


(2001)

Hi Albert ,

Yes, I know how your company feels about Hydrofluoric Acid, it is a real problem to handle but if you use Ammonium Bifluoride in an acid solution you achieve the same results as HF but without the handling problems. Try the following mixture

- 18% by volume of 70% Nitric, 6% by weight of Ammonium Bifluoride and 2% by Volume Hydrochloric Acid.

You may need about 20 minutes immersion at room temperature of 15 °C. The etch time decreases with temperature & the reaction is mildly exothermic.

This is the technology of choice for treating S/S pipe manufactured by welding techniques.

Regards

John Tenison-Woods
John Tenison - Woods
- Victoria Australia


(2001)

Another option is approx. 400 g/l sulphuric acid used anodically at 6V for approx. 10 secs. The current drawn is heavy so make sure all of the wiring and contacts are big.

Martin Trigg-Hogarth
Martin Trigg-Hogarth
surface treatment shop - Stroud, Glos, England



This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site

ADD a Q or A to THIS thread START a NEW THREADView CURRENT TOPICS

Disclaimer: It's not possible to 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 may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices


©1995-2017 finishing.com     -    Privacy Policy
How Google uses data when you visit this site.