Yuhong Group Co.,Ltd
Yuhong Holding Group Co.,LTD
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ASTM A790 S31803 Duplex Stainless Steel Pipe | UNS S31803 | High Strength Corrosion Resistant Pipes
Meta Description:
Manufacturer of ASTM A790 S31803/2205 duplex steel pipes. Certified EN 10204 3.1, 100% hydro tested, PREN >38. Ideal for offshore, chemical & oil/gas. Request specs.
Our ASTM A790 seamless duplex pipes (UNS S31803) combine austenitic and ferritic microstructures, delivering 2x the yield strength of 316L stainless steel with exceptional chloride stress corrosion cracking (SCC) resistance. Ideal for high-pressure, corrosive environments.
Key Advantages:
Table: Balanced Chemistry of S31803 Duplex Steel Pipe
| Element | Min | Max | Target | Role in Performance |
|---|---|---|---|---|
| Cr | 21.0 | 23.0 | 22.0 | Pitting/Corrosion Resistance |
| Ni | 4.5 | 6.5 | 5.5 | Austenite Stability |
| Mo | 2.5 | 3.5 | 3.0 | Chloride Resistance |
| N | 0.08 | 0.20 | 0.15 | Strength & PRE Boost |
| Mn | - | 2.0 | 1.2 | Deoxidation |
| C | - | 0.030 | 0.02 | Weldability |
| S | - | 0.020 | 0.001 | Machinability |
| P | - | 0.030 | 0.025 | - |
| Fe | Balance |
Table: Cross-Standard Material Equivalents
| Standard | Grade | Common Name | Similarity |
|---|---|---|---|
| UNS | S31803 | Duplex 2205 | Identical |
| EN | 1.4462 | X2CrNiMoN22-5-3 | Direct Equivalent |
| ASME | SA790 | - | Parent Spec |
| GOST | 03Kh22N6M2 | - | Comparable |
| JIS | SUS 329J3L | - | Near Match |
Table: Room-Temperature Mechanical Properties per ASTM A790
| Property | Requirement | Typical Value | Advantage vs. 316L |
|---|---|---|---|
| Tensile Strength | ≥ 620 MPa | 750-895 MPa | +40% Higher |
| Yield Strength (0.2%) | ≥ 450 MPa | 550-625 MPa | 2x Higher |
| Elongation (%) | ≥ 25% | 28-35% | Superior Ductility |
| Hardness (Rockwell C) | ≤ 32 HRC | 28-32 HRC | Optimal for Sour Service |
| Impact Toughness | ≥ 100 J (-50°C) | ≥140 J | Arctic Readiness |
Table: Permissible Variations per ASTM A790/ASME B36.19
| Parameter | Tolerance (Seamless Pipe) | Critical Application Focus |
|---|---|---|
| OD (Outer Diameter) | ±0.8% or ±0.2mm* | Fitting Compatibility |
| Wall Thickness | +20% / -12.5% | Pressure Integrity |
| Straightness | ≤ 0.2% of length | Offshore Installation |
| Cut Length | +3mm / -0mm | Welding Efficiency |
Corrosion-Demanding Environments: