Tank is rapidly deteriorating [Georgia]

Micheline,

You could have a problem with "stray" currents that may accelerate the deterioration. Stray currents can come from a number of places. These could include faulty electric heaters, bad temperature probes, or even other sources not associated with the tank, traveling through steel support structures or hoists, etc.

Best of Luck,

Hello Micheline. Did it fail at or adjacent to the welds, but nowhere else? That would be my guess. The heat generated during the welding of the tank is sufficient to cause the chromium and the carbon in the alloy to precipitate as a chromium carbide which leaves the heat effected zone (weld area) without any significant corrosion protection. The use of 316L instead of 316 reduces the amount of carbon available and leaves more alloyed chromium free to form corrosion resistant oxides instead of carbides. Pickling or mechanically polishing the welds after welding also helps to restore corrosion resistance in the welding zone. Instead of SS, I always recommend CPVC, PVC or PVC-lined tanks for Type II passivate solutions. Polypropylene is my recommended tank material for most of the passivate solutions that do not contain chromates. These materials avoid several potential problems. Good Luck.