Duplex Stainless Steel
UNS S31803 – UNS S32205
Duplex Plate/Sheet
Duplex Seamless & Welded Tube
Duplex Seamless & Welded Pipe
Duplex Round Bar
Duplex Flanges F51
Duplex Specialty Forgings
Duplex Seamless & Welded BW Fittings
Trade Name | UNS | Duplex Industry Specifications | Chemical Composition | Min.Tensile (KSI) | Min.Yield (KSI) | Elongation % |
---|---|---|---|---|---|---|
SAF 2205® 22Cr | UNS S31803 | ASME SA-182 (F51), SA-240, SA-798, SA-790, SA-815 ASTM A182 (F51),A240, A276, A479, A789, A790, A815, A928, A988 SAE J405 | C 0.30 max Cr 21.0-23.0 Mn 2.00 max Mo 2.50-3.50 N 0.08-0.20 Ni 4.50-6.50 P 0.030 max S 0.020 max Si 1.00 max | 90 | 65 | 25 |
SAF 2205® 22Cr | UNS S32205 | ASME SA-182 (F60), SA-240, SA-798, SA-790, SA-815 ASTM A182 (F60), A240, A276, A479, A480, A798, A790, A815, A928, A988 SAE J405 | C 0.30 max Cr 22.0-23.0 Mn 2.00 max Mo 3.00-3.50 N 0.14-0.20 Ni 4.50-6.50 P 0.030 max S 0.020 max Si 1.00 max | 95 | 65 | 25 |
SAF 2205® is a registered trademark for Sandvik
General Duplex stainless steel information
The most widely used duplex (ferritic/austenitic) stainless steel grade is 2205 due to both its high strength and resistance to corrosion resistance. Over the years, the composition of duplex S31803 has been further refined, resulting in 1996 in the endorsement of restricted composition range Duplex UNS S32205. S32205 provides better corrosion resistance. In fact, much of the Duplex S31803 currently produced also complies with Duplex S32205. 2205 is not generally suitable for temperatures above 300ºC due to precipitation of brittle micro constituents, nor below -50ºC because of its ductile-to-brittle-transition.
Duplex Applications
- Chemical processing, transport and storage,
- Oil and Gas exploration and processing equipment,
- Marine and other high chloride environments,
- Pulp and paper digesters, liquor tanks and paper machines.
Duplex Corrosion Resistance
S32205 offers excellent general corrosion resistance and is superior to Grade 316 in most environments, providing excellent resistance to localized corrosion including intergranular, pitting and crevice corrosion. The CPT of S32205 is generally at least 35ºC with resistance to chloride stress corrosion cracking (SCC) at temperatures of up to about 150ºC. With better sea water resistance than Grade 316, S32205 often performs well in environments where premature failure of austenitic grades is observed.
Duplex Heat Resistance
Duplex stainless steels are almost never used in environments above 300ºC. While the grade has good resistance to high temperature oxidation S32205, like other duplex stainless steels, suffers from embrittlement even for short periods in temperatures above 300ºC. This can only be rectified by a full solution annealing treatment.
Duplex Heat Treatment
Solution treatment (annealing) entails heating to 1020ºC-1100ºC and then rapid cooling. This grade cannot be hardened by thermal treatment, but does work harden.