Gregbone Type S.S. 316 would be OK - for 10 to 50% Sodium Sulfite upto 100 deg cent with less than 2 mils per year. With salt solution in the system, S.S. 316 may start pitting after a couple of years. Padding with S.S 316 may be OK temporaraily but with base carbon steel corroding this will give further problems. Nz blanketing with carbon stell may not solve the basic corrosion problem. Carbon steel for this concentration of Sodium sulfite will corrode at 50 mils per year. Trust this is of help to you. C.V.Srinivasan Nishi Engineers Pvt Ltd Chennai India July 12 E-mail:nishi@vsnl.com >I have a 15% sodium sulfite (Na2SO3) solution being stored >in an atmospheric tank constructed of carbon steel. All >associated piping is constructed of carbon steel. I have >had numerous small leaks on the piping and a ring of >corrosion inside the tank at approximately the mid-point. I >have contacted the manufacturer of the Na2SO3 and was told >their equipment is constructed of 316ss. The person I spoke >with could not give me any info on corrosion rates for 316 >or carbon steel. I was wondering if anyone is using carbon >steel components in this service and what successes/problems >they have had. Would padding the tank with N2 help the >situation? The solution is basically salt water and I would >think there would be some underdeposit corrosion going on, >espicially with an O2 rich enviroment to drive the process.