We thank you for the answer concerning the corrosion effect of 20% sulfuric acid on SS316L (http://www.chemicalprocessing.com/experts/answers/2009/070.html). It is difficult for us to locate alloy 20 just a few plates to be used in fabrication work as raw material from the commercial market. Only SS316L is available. If recommended thickness is 8mm but if we go in for 10 mm keeping in view the rate of corrosion over a period of time, will this work? What is the approximate time frame anticipated and can the tank last for about 15 years while sustaining the corrosion effect during this time period?
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Brian Dalder Forum Moderator 169 Posts
Re: Corrosion of Metals in Sulfuric Acid26 May 2009 at 1:29pmThe corrosion of metals in sulfuric acid is complex and minor differences in impurities, velocity, or concentration may significantly impact corrosion rates. When austenitic stainless steels like 316L corrode they usually do so by means of a form of localized corrosion like pitting, stress corrosion cracking, intergranular attack, etc. I am not familiar with the specifics of corrosive attack of austenitic stainless steel by sulfuric acid, but if localized corrosion occurs, a corrosion allowance (increasing the metal thickness) will offer no benefit. Corrosion allowances are only helpful when uniform corrosion can occur. You might consider running a corrosion test in the laboratory to simulate the exact conditions of your process to gain additional insight and determine what types of corrosion may be seen in actual service.