Application conditions of RS-2 and Incoloy 825 high-grade stainless steels in chlorinated aqueous solutions

Thread Content

RS-2 (OCr20Ni26Mo3Cu3Si2Nb) stainless steel is a domestically produced Cr–Ni–Mo–Cu stainless steel. Its resistance to pitting and crevice corrosion is equivalent to that of type 316, while its resistance to stress corrosion is better. It can be used with concentrated sulfuric acid (concentration 90–98%) at temperatures below 80 °C, with an annual corrosion rate of ≤0.04 mm/a. Incoloy825 (S) is a high-grade stainless steel composed of Ni (40%)–Cr (22%)–Mo (3%). Incoloy is a registered trademark of Thennational Nickel Co. Suitable for sulfuric acid of various concentrations at low temperatures ； It exhibits good corrosion resistance in caustic alkali solutions (such as NaOH) with concentrations of 50% to 70%, and does not suffer from stress corrosion cracking. However, it is highly sensitive to crevice corrosion caused by chlorides. Furthermore, its stamping performance is also poor, so it is not a commonly used material for sheets.