Sulfuric acid is an important fundamental chemical raw material, its output value is often a symbol of a country’s industrial development level. For the production of acid equipment and acid-filled tanks, containers and other general selection of acid-resistant stainless steel pipe. Although sulfuric acid is an oxygenic acid, dilute sulfuric acid and medium concentration of sulfuric acid oxidation is weak, so they are attributed to the reductive acid. And concentrated sulfuric acid, especially hot concentrated sulfuric acid is a strong oxidizing, and thus attributed to oxidizing acid. Because of this characteristics of sulfuric acid, in the selection of sulfuric acid resistant stainless steel pipe, with the sulfuric acid concentration, the temperature is not the same, the selected grades are not the same.
Dilute sulfuric acid, medium concentration of sulfuric acid is reduced, can be selected 316 stainless steel pipe, 316L stainless steel pipe, 316Ti stainless steel pipe containing molybdenum in 2% to 3% of the stainless steel pipe. Molybdenum-free stainless steel pipe 18-8 Cr-N austenitic stainless steel, because it is not resistant to dilute sulfuric acid, medium concentration of sulfuric acid corrosion, it can not be used for sulfuric acid corrosion situation. When the high molybdenum content (Mo ≥ 4%), the corrosion resistance of the stainless steel pipe will be further improved. Steel containing molybdenum, copper, silicon (3% to 4%) of chromium-nickel austenitic stainless steel and duplex stainless steel pipe resistance to sulfuric acid better.
In the concentration of 90% to 98% of the high temperature concentrated sulfuric acid, according to the use of temperature and concentration, the choice of silicon about 6% of stainless steel can get a satisfactory effect, such as 022Cr17Ni17Si6,022Cr18Ni20Si6MoCu.
In the production of pickling, synthetic rubber, rayon dipping tank and sulfuric acid touch equipment, optional 06Cr18Ni18Mo2Cu2Ti stainless steel pipe. In the production of sulfuric acid corrosion resistant pipes, pumps, valves, towers and containers and other equipment and components, can choose 06Cr12Ni25Mo3Cu3Si2N stainless steel pipe.
Source: China Steel Pipe Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)