Duplex 2205 stainless steel is resistant to chlorides and H2S. Is a problem solver in most industry segments. Duplex 2205 is utilized in heat exchangers and piping in oil and gas, oil refinery, chemical and petrochemical industry.
The design strength of 2205 is significantly higher than 316/316L, often permitting lighter wall construction. 2205 has good notch impact toughness down to temperatures below 40°F. Duplex is welded with E2209 or ER2209 fillers.
Grade 2205 stainless steel exhibits excellent corrosion resistance, much higher than that of grade 316. It resists localized corrosion types like intergranular, crevice and pitting. The CPT of this type of stainless steel is around 35°C. This grade is resistant to chloride stress corrosion cracking (SCC) at temperatures of 150°C. Grade 2205 stainless steels are apt replacements to austenitic grades, especially in premature failure environments and marine environments.
The high oxidation resistance property of Grade 2205 is marred by its embrittlement above 300°C. This embrittlement can be modified by a full solution annealing treatment. This grade performs well at temperatures below 300°C.
The best suited heat treatment for this grade is solution treatment (annealing), between 1020 – 1100°C, followed by rapid cooling. Grade 2205 can be work hardened but cannot be hardened by thermal methods.
The machinability of this grade is low due to its high strength. The cutting speeds are almost 20% lower than that of grade 304. The fabrication of this grade is also affected by its strength. Bending and forming of this grade requires equipment with larger capacity. Ductility of grade 2205 is lesser than austenitic grades; therefore, cold heading is not possible on this grade. In order to carry out cold heading operations on this grade, intermediate annealing should be carried out.
Some of the typical applications of duplex steel grade 2205 are oil and gas exploration, processing equipment, transport, storage and chemical process, high chloride and marine environments, paper machines, liquor tanks, pulp and paper digesters.