Can material 321 be used in 98% concentrated sulfuric acid at a distillation temperature of 180–220 degrees?

321 stainless steel (UNS S32100) is a stabilized austenitic stainless steel material that contains titanium, and it possesses excellent corrosion resistance and heat resistance. However, in extreme corrosive environments such as high-concentration sulfuric acid, its performance needs to be carefully evaluated. For 98% concentrated sulfuric acid, the corrosion resistance of 321 stainless steel is not satisfactory even at room temperature. At higher temperatures, such as during distillation at 180 to 220°C, the corrosion resistance may further decrease. In such an environment of high temperature and high concentration of concentrated sulfuric acid, 321 stainless steel may suffer severe corrosion, particularly intergranular corrosion and stress corrosion cracking. Generally, for applications involving high-concentration sulfuric acid, materials such as high-silicon iron (e.g., silicon-resistant cast iron), special alloys (such as Hastelloy C276, Hastelloy B2, etc.), and titanium are preferred, as these materials offer more reliable performance in highly corrosive environments. When selecting materials, various factors such as the concentration of the medium, temperature, flow rate, and the presence of mechanical stress must be taken into account. For safe and reliable operation, it is recommended to consult the material supplier or a corrosion engineer to conduct a detailed assessment of the material’s corrosion resistance under such conditions; laboratory tests may also be necessary to obtain more specific guidance. .