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sulfuric acid anodizing tank material

Is it permissible to use a stainless steel grade 316 in manufacturing a tank for sulfuric acid anodizing? Knowing that the anodizing solution is 20% sulfuric acid by weight and is operated at a controlled temperature of 20c. If it is not permissible please state the reasons.

Fuad Tufaili
- Beirut, Lebanon
2002

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2002

Fuad,

Going by corrosion data, then it's OK to use 3l6 s.s. for your given conditions.

I would, however, strongly consider approaching any colleagues (and competitors!) to get their ideas and advice. It might well pay off.

The disadvantage of stainless units sure seems to be in the welding ... not so much that the wrong weld rod is used but that the necessary welding temperature will be higher than the melting points of some of the alloys ...! and when that happens, you get weld area failures (eventually).

Being 100% biased, I'd consider, if possible, a flexible PVC liner. To prevent liner (scratch and tear) damage, consider a plastic ledge bolted down to the tank flange and extending inwards by, say, 1/2" or 3/4" ... using, say, min. 1/2" thick h.d. Pe or PP. You should also be able to get away with a bonded fibreglass layer BUT with this heterogenous material it is MOST necessary to prevent any (scratching) of the liner.

Food for thought, anyhow.

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).

Dear SIR,

For tanks to contain acids lead is perfect but I know it is not easy to make. So I suggest to make this bath from fiberglass but first layer is made of anti acid polyester or anti acid polyester mixed with Fumed Silica [affil links]. By the way fiber glass will give good ability to fix your cooler tubes.

Thanks and best regards

RAAFAT ALBENDARY
electroplating - Cairo, Egypt
2002