This type of steel contains very low carbon, nitrogen; high chromium, molybdenum, titanium, niobium and other elements. Such as China's 00Cr17Mo, 00Cr18Mo2, 00Cr26Mol, 00Cr30Mo2 and foreign 18-2, Cr26Mol, 25Cr-5Ni-4Mo-Nb, MoNiT, Al29-4, Al29-4-2. This type of steel has good mechanical properties (especially toughness), weldability, intergranular corrosion resistance, pitting corrosion resistance, crevice corrosion resistance, and excellent stress corrosion cracking resistance. For example, 18-2 has good corrosion resistance in nitric acid, acetic acid, and NaOH. The pitting corrosion resistance in 3% NaCl and FeCl3 is equivalent to or more than 18-8 austenitic steel, and the SCC resistance far exceeds 18-8 steel. 26CrMo steel is resistant to corrosion in many media, especially organic acids, oxidizing acids, and strong alkalis. It has good pitting resistance in strong chloride medium. There is no stress corrosion cracking in chloride, hydrogen sulfide, excessive sulfuric acid and strong alkali. 30Cr-2Mo has higher resistance to pitting and crevice corrosion while maintaining stress corrosion resistance. Steel with a small amount of nickel can improve its performance in reducing acids.
