ASTM A790 S31803/S32205 Duplex Stainless Steel Pipe Manufacturer
UNS S31803 or S32205 duplex stainless steel ,1.4462 combines good mechanical strength, moderate to good corrosion resistance and superior pitting resistance
ASTM A790 specification covers seamless and straight-seam welded ferritic/austenitic steel pipe for general corrosive service
S31803/S32205 refers to a specification for duplex stainless steel seamless and welded pipes. These grades are commonly known as Duplex 2205, which offers excellent corrosion resistance, high strength, and good weldability.
Character of UNS S31803
Material to UNS S31803 is described as a duplex stainless steel with a microstructure of 50:50 austenite and ferrite. The steel combines good mechanical strength (typically up to over 480 MPa yield strength) and ductility with moderate to good corrosion resistance in a variety of environments. By agreement, the alloy can be supplied with a PREN (Pitting Resistance Equivalent) at >34 which ensures that the resistance to pitting corrosion is as high as possible for this alloy grade. In addition, the steel offers good resistance to stress corrosion cracking. Ambient and subzero temperature notch ductility is good. These attributes mean that this duplex steel can be used successfully as an alternative to 300 series stainless steels in applications where higher mechanical strength / lower weight is required and / or resistance to stress corrosion cracking is needed
DUPLEX STEEL UNS S31803 Pipe Dimension range
| Stainless Steel Seamless Pipe | ASTM A790/A790M: OD: Φ6mm-Φ325mm; WT:0.5mm-30mm |
| Stainless Steel Welded Pipe | ASTM A790/A790M: OD: Φ10mm-Φ2000mm; WT:0.5mm-40mm(OD≤630mm for single seam; OD＞Φ630mm For circumferential seam) |
| ASTM A928/A928M: OD: Φ10mm-Φ406mm; WT:0.5mm-10mm |
DUPLEX STEEL A790 UNS S31803 PIPE CHEMICAL COMPOSITION
| Grade | C | Mn | Si | P | S | Cr | Ni | Mo | N | Fe |
| Duplex S31803 | 0.030 max. | 2.00 max. | 1.00 max. | 0.030 max. | 0.020 max. | 22.0 – 23.0 | 4.50 – 6.50 | 3.0 – 3.5 | 0.14 – 0.20 | 63.72 min. |
| Duplex S32205 | 0.030 max. | 2.00 max. | 1.00 max. | 0.030 max. | 0.020 max. | 21.0 – 23.0 | 4.50 – 6.50 | 2.50 – 3.50 | 0.08 – 0.20 | 63.54 min |
Mechanical Properties and hardness of UNS S31803
| UNS | Tensile Strength Min, Mpa | Yield Strength Min, Mpa | Elongation in 2 in Or 50mm Min, % | Hardness Max, HRC |
| S31803 | 620 | 450 | 25 | 30 |
| S32205 | 655 | 485 | 25 | 30 |
UNS S31803 ,S32205 Heat Treatment
The solution temperature is around 1100°C, and rapid cooling.
| UNS Designation | Temperature | Quench |
|---|---|---|
| S31803 | 1870-2010 °F [1020-1100°C] | Rapid Cooling In Air Or Water |
| S32205 | 1870-2010 °F [1020-1100°C] | Rapid Cooling In Air Or Water |
UNS S31803/S32205 Weldability
UNS S31803/S32205 (1.4462 has good weldability similar to that of other stainless steel types. Low thermal expansion reduces residual stresses after welding. Use duplex welding electrodes similar to that of the parent steel when welding UNS S31083. Electric arc welding processes are suitable though oxyacetylene welding is not recommended due to the possibility of carbon pick up in the weld area of the UNS S31803. Whilst post weld annealing is not a requirement for many applications it will give optimum corrosion resistance in severe service conditions. We recommend you contact your welding consumables supplier who should provide you full assistance and information of welding UNS S31803 duplex.
Applications of ASTM A790 S31803 Pipe
- Oil & Gas Pipelines
- Chemical & Petrochemical Processing
- Desalination & Water Treatment Plants
- Marine & Offshore Structures
- Heat Exchangers & Pressure Vessels
Dimension Tolerance of ASTM A790 S31803 Pipe
Accoridng to ASTM A790,UNS S31803 Pipe Material furnished under this specification shall conform to the applicable requirements of the current edition of Specification A 999/A 999M unless otherwise provided herein.
Wall thickness tolerance
Outside Diameter tolerance
What is the difference between S31803 and S32205 ?
Both 31803 and 32205 are duplex stainless steels grade, they have excellent strength and corrosion resistance. However, there are some differences between this 2 grades
From the above chemical and mechanical property table.We can easily found the difference
- Chemical Composition:
- 31803 (UNS S31803) is the original duplex stainless steel composition.
- 32205 (UNS S32205) is an improved version of 31803 with a slightly higher nitrogen content, which enhances its strength and corrosion resistance.
- Corrosion Resistance:
- 32205 has better pitting, crevice, and general corrosion resistance compared to 31803, particularly in harsh environments like marine and chemical processing industries.
- Mechanical Properties:
- Due to its higher nitrogen content, 32205 has slightly better yield and tensile strength than 31803.
In General,UNS S32205 is used as a direct replacement for 31803 since it meets or exceeds the requirements of 31803.
