I have a large storage tank of 93% sulfuric acid. I am having excessive corrosion of the top of the 4-inch carbon steel outlet pipe. I am thinking of replacing the outlet pipe with Schedule 120 carbon steel pipe. Is there any more resistant material, insert, or coating you could recommend for increased life?
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Brian Dalder Forum Moderator 177 Posts
Re: Can you suggest a corrosion-resistant material?7 August 2009 at 1:29pmCarbon steels are only acceptable for 93% sulfuric acid when fluid velocity is low (< 3 ft/sec). For 4-inch diameter piping or less with velocities up to 5.9 ft/sec, 316L stainless steel is a good choice. For velocities higher than 5.9 ft/sec, Alloy 20Cb-3 (UNS N08020) has been used successfully. For additional information, consult NACE Recommended Practice RP-0391 "Materials for the Handling and Storage of Commercial Concentrated (90 to 100%) Sulfuric Acid at Ambient Temperatures."