GNEE is a well-known manufacturer, exporter, distributor, stockist and supplier of stainless steel duplex pipes. Our products comply with domestic and international raw material quality standards.
We provide ASTM A789 UNS S31803 duplex stainless steel pipes in a full range of sizes, including both welded and seamless variants. Endowed with high strength and excellent corrosion resistance, duplex stainless steel pipes are ideal for service in harsh operating environments.
ASTM A789 UNS S31803 stainless steel heat exchanger tubes adopt an optimized thin-wall design-with a 20%–30% reduction in wall thickness under the same pressure rating. This design not only cuts the overall weight of heat exchangers by 15%–20% but also increases the heat exchange area per unit volume, thereby enhancing heat transfer efficiency. Meanwhile, ASTM A789 UNS S31803 boiler tubes can withstand no less than 10⁶ cycles of temperature alternation (-50℃ to 300℃) without cracking, perfectly adapting to the frequent start-stop working conditions of heat exchangers.
Compared with ordinary steel tubes, UNS S31803 stainless steel superheater tubes reduce fluid flow resistance by 12% and further improve heat transfer efficiency by 8%–10%. In addition, these products are fully compliant with ASME SA789 and NACE MR 0175/ISO 15156 standards, ensuring the long-term stable operation of heat exchangers in harsh working environments such as chemical processing and oilfield waste heat recovery.
Specifications
SA 789 UNS S31803 chemical composition
| UNS | 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 | - | - |
ASTM A789 S31803 mechanical properties
| Grade | Tensile Strength (MPa) min |
Elongation (% in 50mm) min |
Yield Strength 0.2% Proof (MPa) min |
Hardness | |
| Rockwell C (HR C) | Brinell (HB) | ||||
| UNS S31803 | 621 | 25 | 448 | 31 max | 293 max |
ASTM A789 S31803 condenser tube Tolerance
| Nominal pipe size up to 4 = ± 0.79 milimeter | 5 thru 8 = + 1.58 mm / - 0.79 milimeter 10 thru 18 = + 2.37 mm / - 0.79 milimeter | 20 thru 24 = + 3.18 mm / - 0.79 milimeter | ||
| Wall Thickness All Dia = - 12.5% + tolerance not specified | Weight Weight = + 10% / - 1.5% | Length + 6.40 mm / - 0 milimeter |
A789 UNS S31803 Heat Exchanger Tubes Temperature Range
| Product | Temperature Range |
|---|---|
| UNS S31803 Tubing | Up to 600°F (316°C) |
ASTM A789 UNS S31803 Tube Pressure Rating
| Tube O.D. (In.) |
Wall Thickness Of Tube (Inches) | |||||||
|---|---|---|---|---|---|---|---|---|
| Working Pressure (Psig) | ||||||||
| .120 | .095 | .028 | .065 | .035 | .083 | .049 | .109 | |
| 5/16 | 7300 | 3700 | 5400 | |||||
| 1/8 | 7900 | 10100 | ||||||
| 3/8 | 6100 | 3100 | 4400 | |||||
| 3/4 | 4600 | 3000 | 4000 | 2200 | ||||
| 1/4 | 3700 | 9500 | 4800 | 7000 | ||||
| 1 | 4300 | 3400 | 2200 | 2900 | 3900 | |||
| 1/2 | 4400 | 2300 | 3200 | |||||
ASTM A789 UNS S31803 Tube Price List
| Price list | Price in USD |
|---|---|
| ASTM A789 UNS S31803 Tube Size: 6.35 x 0.35 mm | US $ 3.50 |
| A789 S31803 Tube Size: 25.4 x 1.0 mm | US $ 10.00 |
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Testing and Inspection
We cut Duplex 2205 tubing to your exact dimension
Reverse Flattening Test
Flaring Test
Flange Test
Nondestructive Testing
Moisture testing
PMI Test
Highest quality packaging and shipping
Packaging:
Tubes must be packed safely in strong wooden boxes or wooden bundles with:
.Plastic caps
.Moisture protection (VCl)
.Internal separators
Straps
Customer Visit
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