Erfahrungen mit zwei hochlegierten,hochkorrosionsbeständigen Stählen in der chemischen Industrie

Experience from the chemical industry of the use of two high-alloy, highly corrosion resistant steels The steels SANDVIK 2RK65 and 2RE69 described in the article are fully austenitic and have the following nominal compositions:

• 2RK65 = Steel A' ? 0,020 C, 19, s Cr, 25 Ni, 4.5 Mo, 1,5 Cu,
• 2RE69 = Steel B ?0,020 C, 25 Cr, 22 Ni, 2,1 Mo, 0.12 N

Steel A has mechanical properties corresponding to most austenitic stainless steels, whereas Steel B, which is nitrogen alloyed, has somewhat higher strength. Besides very good resistance to non-oxidizing acids such as sulphuric acid and phosphoric acid and to all organic acids, Steel A has excellent resistance to pitting and good resistance to stress corrosion cracking. From the use of tubes of Steel A in highly corrosive environment in various chemical plants, considerable experience is now available, some of which is reported in this article. Steel B is a new steel up to now mainly used as stripper tubes in urea plants. Steel B is characterized by outstanding resistance in oxidizing acid solutions also in the presence of chlorides. As in the case of standard austenitic steels, neither of these two steels offer any fabrication problems.