what is SA789 UNS S31803 chemical Composition？
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What is SA789 S31803 material pipe?
ASTM A789 / A 789M, ASME SA789 S31803 Duplex Stainless Tubing is for Boilers, Superheaters and Heat Exchangers. ASTM A789 /A789M Covers Grades of nominal wall thickness, stainless steel tubing for services requiring general corrosion resistance, with particular emphasis on resistance to stress corrosion cracking.
What is the equivalent material for SA789 UNS S31803 stainless steel?
The primary equivalent material for SA789 UNS S31803 stainless steel is UNS S32205 (often referred to as 2205 or SAF 2205), along with DIN 1.4462 and X2CrNiMoN22-5-3. This duplex grade,, known for its high corrosion resistance, is commonly used in chloride environments, oil and gas, and chemical processing.
Manufacture & Heat Treatment
ASTM A789/A789M UNS 31803 tubes shall be made by the seamless or welded process with no filler metal added. It shall be quenched in cool air or water rapidly to a temperature of 1800°F[980°C]-1900°F[1040°C]. For seamless tubes, as an alternative to final heat treatment in a continuous furnace or batch-type furnace, while the tube temperature is not lower than the specified minimum solution treatment temperature, tubes may be immediately quenched in water or rapidly cooled by other means.
what is SA789 UNS S31803 chemical Composition?
SA789 UNS S31803 is a standard, nitrogen-enhanced duplex stainless steel (approx. 50% austenite/50% ferrite) commonly known as Duplex 2205 or DIN 1.4462. Its chemical composition, optimized for corrosion resistance, includes 21.0-23.0% Chromium (Cr), 4.5-6.5% Nickel (Ni), 2.5-3.5% Molybdenum (Mo), and 0.08-0.20% Nitrogen (N), with maximum 0.030% Carbon.
| UNS Designation |
Composition, % | ||||||||||
| C Max |
Mn max |
P max |
S max |
Si max |
Ni | Cr | Mo | N | Cu | Others | |
| S31803 | 0.03 | 2 | 0.03 | 0.02 | 1 | 4.5-6.5 | 21.0-23.0 | 2.5-3.5 | 0.08-0.20 | . . . | . . . |
Mechanical Properties
| Tensile Strength,min. | Yield Strength,min. | Elongation,min. | Hardness Brinell, max |
|---|---|---|---|
| Mpa | Mpa | % | HB |
| 620 | 450 | 25 | 290 |
ASTM A789 UNS S31803 Tube Size Chart
| DN | NPS | D | Schedule | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Inch | mm | XXS | 5S | 160 | 80S | XS | 80 | 40 | STD | 40S | 10S | |
| 6 | 1/8 | 10.30 | 2.41 | 2.41 | 2.41 | 1.73 | 1.73 | 1.73 | 1.24 | |||
| 8 | 1/4 | 13.70 | 3.02 | 3.02 | 3.02 | 2.24 | 2.24 | 2.24 | 1.65 | |||
| 10 | 3/8 | 17.10 | 3.20 | 3.20 | 3.20 | 2.31 | 2.31 | 2.31 | 1.65 | |||
| 15 | 1/2 | 21.30 | 7.47 | 1.65 | 4.78 | 3.73 | 3.73 | 3.73 | 2.77 | 2.77 | 2.77 | 2.11 |
| 20 | 3/4 | 26.70 | 7.82 | 1.65 | 5.56 | 3.91 | 3.91 | 3.91 | 2.87 | 2.87 | 2.87 | 2.11 |
| 25 | 1 | 33.40 | 9.09 | 1.65 | 6.35 | 4.55 | 4.55 | 4.55 | 3.38 | 3.38 | 3.38 | 2.77 |
SA 789 UNS S31803 tube pressure rating
Dimensions: wall tolerance: ± 10%, OD 3.18mm x 0.89mm
| Grade |
Maximum internal pressure, bar |
||||||||
|---|---|---|---|---|---|---|---|---|---|
| 20°C | 50°C | 100°C | 150°C | 200°C | 250°C | 300°C | 350°C | 400°C | |
| 1.4462 (SAF 2205) |
1612 | 1612 | 1451 | 1350 | 1249 | 1189 | - | - | - |
Pressure rating of SA789 S31803 tubing As per ASME B31.3 American standard
Dimensions: wall tolerance: ± 10%, OD 3.18mm x 0.89mm
| Grade |
Maximum internal pressure, bar |
||||||||
|---|---|---|---|---|---|---|---|---|---|
| 100°F | 200°F | 300°F | 400°F | 500°F | 600°F | 700°F | |||
| S31803 (SAF 2205) |
1251 | 1251 | 1205 | 1159 | 1134 | 1121 | - | ||
For ASTM A789 UNS S31803 tubing, if the lot size does not exceed 50 tubes, one sample shall be selected for tensile testing; if the quantity exceeds 50 tubes, two tubes shall be selected as samples for tensile testing. One end of each finished tube shall be subjected to a flaring test (for seamless tubes) or a flanging test (for welded tubes). The minimum flaring expansion of the inside diameter shall be 10%.
If requested by the purchaser, a hydrostatic test shall be performed in accordance with Specification A1016/A1016M; however, the hydrostatic test pressure shall be calculated using the value 64,000 (441.2) instead of 32,000 (220.6).
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What is the difference between S31803 and SS316?
UNS S31803 (2205 Duplex) is a high-strength, superior corrosion-resistant duplex stainless steel (22% Cr) often used in harsh environments, whereas SS316 is a standard austenitic stainless steel (18% Cr) chosen for its versatility and lower cost. S31803 provides roughly double the yield strength, superior pitting resistance, and chloride stress corrosion cracking resistance compared to SS316.
If you have project-specific requirements for ASTM A789/A789M UNS 31803 tubes, we welcome your orders. GNEE maintains a substantial inventory of our best-selling products for you to choose from. These tubes are available in both seamless and welded forms; for detailed chemical composition specifications or to request free samples, please contact our facility immediately. We offer competitive pricing and exceptional service.
Our products are packaged using waterproof paper and steel strapping, adhering to standard export packaging requirements for maritime transport and are suitable for various modes of shipping; alternatively, packaging can be customized according to client specifications.
Packaging
Standard Export Packaging for Stainless Steel Plates
1. Polished surface finish; 2. Bundled packaging;
3. Wooden crate packaging; Wooden pallet packaging.
