SS 316 pipes are rusting.

[adnans]

WE ARE FACING RUSTING PROBLEM TO THE SS 316L pipings,at diffrent places.I mean to say If there is one pipe length on this pipe some places ,rusting is appreaing.Plese giev the suitable ansawer.

 

[CARF]

Chlorinated water?

Stainless steel and Cl- ions are a bad combination.

Put your question again on the corrosion engineering group.

MVD

 

[pablo02]

My experience is that Chlorine will cause stress corrosion cracking but not rusting: One, have you verified that the pipe is actually 316? Two, has anyone used a standard grinding wheel on the areas that show rusting? Follow up on MVD suggestion to post on the corrosion site...

 

[Rich39]

My experience in the maritime area is that unless SS is regularly cleaned, the staining that I assume you are talking about (and not actual corrosion, intergranular or otherwise) can be due to the presence of concentrated chlorides left on the metal's surface, unsightly but rarely fatal. The other reason that springs to mind was touched on by pablo02, has anyone used a grinder on mild steel nearby?

rich39

 

[BRIS]

We have had crevice corrosion problems with sulphate reducing bacteria and have used chlorine dosing to kill the bacteria.

Galvanic corrosion between different due to electrical conductivity between different metals and contamination from mild steel can also be a problem.

Tae the advice above and post on the corrosion site but give them more information to work with.

Is it external or internal corrosion.

What is the liquid.

Is galvanic corrosion between different metals a possibility.

brian

 

[unclesyd]

There are many things that can cause S/S to rust.
As mentioned above please give a little more information as to the location of the "rust", old or new pipe, service,local enviroment. Is the "rust" easily removed with a H3PO4 based commercial cleaner? Check it with a 100% concentation.

One of the more common causes of loacalized "rust" on Austenetic S/S is iron contamination from brushes, sparks from grinding c/s in the area,storage racks,etc. Very fine S/S grinding dust can "rust" under certain conditions. If the rust is on or near the welds check for proper welding procedures. In some enviroments 316 s/s will only stay shinny longer than say 304 s/s.

Watch using any Cl based cleaners and treatments on Austenetic S/S. Is there any halogen based processes in the area?