Corrosion in Stainless Steel from Wastewater

Question

Corrosion in Stainless Steel from Wastewater

ksuengrng (Mechanical)

(OP)

3 May 01 10:12

We have a client who has contacted us about some corrosion his clients are experiencing.  They manufacturing stainless steel products for the wastewater industry and have ran into a recent corrosion problem.

Piping and elbows are SA312-304 S.S.
Other "heavy" stainless is SA240-304 and SA240-304L

Chemical is wastewater:  some aerobic and some anaerobic, pH is low; temperature is ambient, no pressure or vacuum present

Tank and piping is 4 years old.  Some places have seen corrosion bad enough to put two fingers through the hole, others have bad pitting, some the elbow is fine and the pipe threads are gone, some the pipe is ok and the elbow is destroyed.

Have thought about lack of oxygen contributing to this and would like some of the forums expert opinions on this.

Thanks in advance.

Scott

Rich2001 (Mechanical) · Answer 1 · 2001-05-03 12:16:29

I take from you post tht the piping is threaded. The problem is probally do to the fact the Crevice corrosion is a problem with TP 304 stainless steel in many aqueous environments. Changing to a butt welded system might solve some of the problems. In addition, it might behoove them to change the material to a low carbon grade, type 304L.

PH is Low? what is the PH? What are the chemicals used in the processing of the waste water? In many cases the trace chemicals are causing the corrosion.

Get a PI&D of the process and start working your way through it. Mark where to corrosion is occuring then look immediately upstream.

Let us know what you find.

Rich

ksuengrng (Mechanical) · Answer 2 · 2001-05-03 12:21:28

Rich:

Thanks for the quick reply. I am meeting with the client tomorrow and will keep you informed of the "progress" and findings.

Scott

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Corrosion in Stainless Steel from Wastewater