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2205 Duplex Stainless Steel Bar
2205 is a (two phase) ferritic/austenitic stainless steel with high strength and excellent corrosion resistance, as supplied in the annealed condition with a maximum brinell hardness of 290 (Rc31). Characterised by high yield strength, double that of the standard austenitic stainless steel grades, good fatigue strength plus excellent resistance to stress corrosion cracking, crevice, pitting, erosion and general corrosion in severe environments. Again generally out performing the standard austenitic stainless steel grades.2205 cannot be hardened by thermal treatment, but strength and hardness can be increased substantially by cold working, with subsequent reduction in ductility.It is used extensively by the Marine, Chemical, Petrochemical, Pulp and Paper, Oil and Gas, Transport and allied processing industries.Typical uses are: Anchor Guides, Conveyors, Fasteners, Bushings, High Strength Pump Shafts, Propellor Shafts, plus various applications currently using standard austenitic stainless steel grades.
Material Magnetic due to its part ferritic structure.
| Related Specifications | |
|---|---|
| German | W.Nr 1.4462 DIN X2CrNiMoN22 5 3 |
| USA | ASTM A276-98b UNS S31803 |
| Chemical Composition | Min. % | Max. % |
|---|---|---|
| Carbon | 0 | 0.03 |
| Silicon | 0 | 1.00 |
| Manganese | 0 | 2.00 |
| Nickel | 4.50 | 6.50 |
| Chromium | 21.00 | 23.00 |
| Molybdenum | 2.5 | 3.5 |
| Nitrgogen | 0.08 | 0.20 |
| Phosphorous | 0 | 0.03 |
| Sulphur | 0 | 0.02 |
| Mechanical Property Requirements - Annealed (As Supplied) to ASTM A276-98b UNS S31803 for Hot and Cold Finished | |||
|---|---|---|---|
| Tensile Strength Mpa (Min) | 0.2 % Yield Strength Mpa ( Min ) | Elongation in 50mm % Min | Hardness HB Max |
| 620 | 448 | 25 | 290 |
| Typical Mechanical Properties at room temperature - Annealed | |||||
|---|---|---|---|---|---|
| Tensile Strength ( Mpa ) | Yield Strength ( Mpa ) | Elongation in 50mm ( % ) | Charpy V Impact (J ) | Hardness | |
| HB | RC | ||||
| 650 - 900 | 570 | 30 | 130 | 235 | 23 |
Elevated Temperature Properties*
While the oxidation resistance of 2205 is good at high temperature as with other duplex stainless steel grades, it is subject to embrittlement when exposed to temperatures above 300 oC even for short periods. It is subject to embrittlement at 475 oC when exposed for 2 hours only, also between 370 oC and 540 oC over a longer period.
Precipitation of sigma phase will also occur above 650 oC resulting in decreased ductility and corrosion resistance.
*2205 is therefore not recommended for use at temperatures above 300 oC.
| Typical Mechanical Properties at Elevated Temperatures for 63.5 mm Dia Section - Annealed Condition | |||
|---|---|---|---|
| Test Temperature oC | Tensile Strength Mpa | Yield Strength Mpa |
Charpy V Notch Impact After 100 Hours at Temp. J |
| 315 | 350 | 390 | 45 |
| 370 | 640 | 375 | 22 |
| 480 | 5 | ||
| N.B. Should embrittlement occur then annealing is required to rectify. | |||
Low Temperature Properties
2205 is not recommended for use at temperatures below -50 oC, again due to its embrittling effect resulting in low ductility.
N.B. Unlike high temperature exposure however, the embrittling effect of low temperature exposure is not permanent, existing only for the duration at low temperature.
| Typical Charpy V-Notch Impact Properties at Low and Sub Zero Temperatures | |
|---|---|
| Test Temperature oC | Impact Test Charpy V-Notch |
| 25 | 160 |
| 0 | 60 |
| -20 | 30 |
| -45 | 15 |
Bending
Cold Bending
Cold bending will be extremely difficult due to the high yield strength. Any cold working causing more than 10% deformation should be followed by annealing.
Hot Bending
Hot bending should be performed at 950 oC - 1000 oC followed by annealing.
Corrosion Resistance
General Corrosion
2205 has superior resistance to general corrosion in most media than 316L or 317L austenitic stainless steel grades。
Stress Corrosion Cracking
2205 has a much higher resistance to stress corrosion cracking than 304L or 316L austenitic stainless steel grades.
Pitting Corrosion
2205 has a higher resistance to pitting corrosion than 316L or 317L austenitic stainless steel grades.
Crevice Corrosion / Erosion Corrosion
2205 has a higher resistance to crevice corrosion and erosion corrosion than 316L austenitic stainless steel grade.
Corrosion Fatigue
2205 has better fatigue strength in corrosive environments than the standard austenitic stainless steel grades due to its higher strength and higher corrosion resistance.
N.B. For optimum corrosion resistance, surfaces must be free of scale and foreign particles.
Finished parts should be passivated.
Forging
Heat uniformly to 1150 oC. Hold until temperature is uniform throughout the section.
Do not forge below 900 oC.
Finished forgings should be air cooled.
Finally forgings will require to be annealed in order to obtain optimum mechanical properties and corrosion resistance.
Heat Treatment
Annealing
Heat to 1020 oC - 1100 oC. Hold until temperature is uniform throughout the section. *Soak as required.
Quench in water to obtain optimum corrosion resistance.
*Actual soaking time should be long enough to ensure that the part is heated thoroughly throughout its section to the required temperature, 30 minutes per 25mm of section may be used as a guide.
Please consult your heat treater for best results.
Machining
The machinability of 2205 in the annealed as supplied condition is lower than either 304 and 316 due to it's higher yield strength (approximately double).
Typically 80% as machinable as the standard 304 and 316 grades, but lower against the improved machinability 304 and 316 grades.
N.B. All machining should be carried out as per machine manufacturers recommendations for suitable tool type, feeds and speeds.
Welding
2205 is readily weldable by the various standard electric arc welding processes.
Oxcyacetylene welding is however not recommended due to the possibility of carbon pick up in the weld area.
