S31260 Duplex Stainless Steel Tube - Chloride Corrosion Resistant High Strength Solution Annealed for Fluid Gas Transport
UNS S31260 is a 25Cr duplex stainless steel tube grade designed for industrial fluid and gas transport where higher strength, chloride corrosion resistance, and stress corrosion cracking resistance are required. Compared with standard 304/316 austenitic stainless steel tubing, S31260 offers a stronger duplex microstructure and higher resistance in chloride-bearing process media, seawater-related systems, mildly sour service, and corrosive industrial transfer lines.
This product can be supplied as seamless tube, welded tube, cold-drawn tube, solution-annealed tube, pickled tube, polished tube, or bright-annealed tube according to the required service condition, dimensional tolerance, surface condition, and inspection level.
| Item | Description |
|---|---|
| Material | Duplex stainless steel |
| Standard | ASTM A789 / ASME SA789, ASTM A790 / ASME SA790, ASTM A928 for EFW pipe if required |
| Grade | UNS S31260 |
| Product Type | Seamless tube / welded tube / cold-drawn tube / industrial pipe |
| Outer Diameter | 6.0-219 mm for tube supply; larger welded pipe sizes can be customized |
| Wall Thickness | 0.5-20 mm; SCH 5S to SCH XXS available for pipe orders |
| Length | 1-12 m, fixed length or random length, customized |
| Tolerance Range | OD: ±0.10 mm to ±1.0% depending on size; WT: ±10% or as agreed by order |
| Straightness | ≤1.5 mm/m typical; tighter straightness available for precision tubing |
| Surface Condition | Pickled, annealed & pickled, bright annealed, polished, brushed, or customized |
| Heat Treatment | Solution annealing followed by rapid cooling / water quenching |
| Manufacturing Method | Seamless, welded without filler metal, cold drawn, cold rolled, or welded + drawn |
| Testing | Chemical analysis, tensile test, hardness test, hydrostatic test or eddy current test, PMI, dimensional inspection |
| Characteristic | Technical Value / Explanation |
|---|---|
| Duplex Structure | Austenitic-ferritic stainless steel structure, providing higher strength than common austenitic grades |
| Chromium Content | 24.0-26.0%, supporting oxidation and chloride corrosion resistance |
| Molybdenum Content | 2.50-3.50%, improving resistance to pitting and crevice corrosion |
| Nitrogen Content | 0.10-0.30%, improving strength and localized corrosion resistance |
| Copper Content | 0.20-0.80%, improving resistance in some acidic and chloride-containing environments |
| Tungsten Content | 0.10-0.50%, contributing to pitting and crevice corrosion resistance |
| Minimum Tensile Strength | 690 MPa minimum |
| Minimum Yield Strength | 450-485 MPa minimum depending on referenced product standard |
| Minimum Elongation | 20-25% minimum depending on referenced product standard |
| Maximum Hardness | 290 HB maximum |
| PREN Reference | Approx. 34-43 calculated from Cr + 3.3(Mo + 0.5W) + 16N, depending on actual heat chemistry |
A common procurement issue is specifying S31260 under an austenitic tubing standard such as ASTM A269. For S31260 duplex stainless steel, we recommend confirming ASTM A789 / ASME SA789 for tubing or ASTM A790 / ASME SA790 for pipe. This avoids mismatched chemical, mechanical, heat-treatment, and inspection requirements at the quotation and MTC stage.
Duplex stainless steel requires correct solution annealing and rapid cooling to maintain corrosion resistance and mechanical performance. We control heat treatment by grade, size, wall thickness, and production route. For welded tubes, flange test, reverse flattening test, hardness test, hydrostatic test, or nondestructive electric test can be arranged according to the purchase specification.
For industrial fluid and gas transport, dimensional accuracy and tube integrity are critical. We can provide chemical analysis, mechanical test report, PMI test, hydrostatic test, eddy current test, visual inspection, OD/WT inspection, and EN 10204 3.1 material certificate. For critical service, third-party inspection can be arranged before shipment.
| Standard System | Applicable Standard | Brief Description |
|---|---|---|
| ASTM / ASME | ASTM A789 / ASME SA789 | Seamless and welded ferritic/austenitic stainless steel tubing for general service |
| ASTM / ASME | ASTM A790 / ASME SA790 | Seamless and welded ferritic/austenitic stainless steel pipe for general corrosive service |
| ASTM / ASME | ASTM A928 / ASME SA928 | Electric-fusion-welded ferritic/austenitic stainless steel pipe with filler metal |
| ASTM | ASTM A959 | Harmonized standard grade designations for stainless steels |
| EN | EN 10216-5 / EN 10217-7 | Stainless steel seamless or welded tubes for pressure purposes, grade equivalence to be confirmed by project specification |
| GOST | GOST 9940 / GOST 9941 | Seamless corrosion-resistant stainless steel tubes; grade substitution requires technical confirmation |
| JIS | JIS G3459 / JIS G3463 | Stainless steel pipes/tubes for corrosion-resisting and heat-exchanger service; equivalent grade must be confirmed |
| GB | GB/T 21833 / GB/T 14976 | Duplex stainless steel seamless pipe or stainless seamless pipe systems; project grade mapping required |
| Application Field | Specific Product |
|---|---|
| Offshore oilfield fluid transport | Seawater injection line tube for offshore platform water-injection systems |
| Grade / UNS | C Max | Mn Max | P Max | S Max | Si Max | Ni | Cr | Mo | N | Cu | W / Others | Fe |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| S31260 | 0.030 | 1.00 | 0.030 | 0.030 | 0.75 | 5.50-7.50 | 24.00-26.00 | 2.50-3.50 | 0.10-0.30 | 0.20-0.80 | W 0.10-0.50 | Balance |
| S31803 | 0.030 | 2.00 | 0.030 | 0.020 | 1.00 | 4.50-6.50 | 21.00-23.00 | 2.50-3.50 | 0.08-0.20 | -- | -- | Balance |
| S32205 | 0.030 | 2.00 | 0.030 | 0.020 | 1.00 | 4.50-6.50 | 22.00-23.00 | 3.00-3.50 | 0.14-0.20 | -- | -- | Balance |
| S32750 | 0.030 | 1.20 | 0.035 | 0.020 | 0.80 | 6.00-8.00 | 24.00-26.00 | 3.00-5.00 | 0.24-0.32 | 0.50 max | -- | Balance |
| S32760 | 0.030 | 1.00 | 0.030 | 0.010 | 1.00 | 6.00-8.00 | 24.00-26.00 | 3.00-4.00 | 0.20-0.30 | 0.50-1.00 | W 0.50-1.00 | Balance |
| Grade / UNS | Tensile Strength Min | Yield Strength Min | Elongation Min | Hardness Max |
|---|---|---|---|---|
| S31260 | 690 MPa | 450-485 MPa | 20-25% | 290 HB |
| S31803 | 620 MPa | 450 MPa | 25% | 290 HB |
| S32205 | 655 MPa | 485 MPa | 25% | 290 HB |
| S32750 | 800 MPa | 550 MPa | 15% | 310 HB |
| S32760 | 750 MPa | 550 MPa | 25% | 300 HB |
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