Super Duplex Stainless Steel ASTM A789 S32520 Pipe
Super Duplex Stainless Steel ASTM A789 S32520 Pipe: High-Strength & Corrosion Resistant Material
Complete material data for ASTM A789 S32520 super duplex stainless steel pipe, including chemical composition, mechanical properties, thermal & electrical properties, international equivalents, and application guidance.
Hot working, cold working, machining, welding (GTAW, SMAW, SAW, etc.), solution annealing
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Super Duplex Stainless Steel ASTM A789 S32520 Pipe Introduction
ASTM A789 S32520 is a super duplex stainless steel characterized by a mixed microstructure of ferrite and austenite, offering an excellent combination of high mechanical strength and superior corrosion resistance, particularly in aggressive chloride-containing environments. This alloy typically contains 25% chromium, 7% nickel, 3.5% molybdenum, along with additions of copper and tungsten, which enhance resistance to pitting, crevice corrosion, and stress corrosion cracking. The grade demonstrates exceptional strength (minimum yield strength of 550 MPa / 80 ksi) while maintaining good ductility and weldability. Commonly known under trade names such as Zeron 100, the material is widely used in the oil & gas, chemical processing, marine, and desalination industries. ASTM A789/A789M covers seamless and welded ferritic/austenitic steel tubing intended for general corrosion-resisting and high-temperature service.
Super Duplex Stainless Steel ASTM A789 S32520 Pipe Chemical Composition
The chemical composition limits conform to the requirements of ASTM A789/A789M for UNS S32520. The alloy is balanced to achieve a duplex microstructure with approximately 50% ferrite and 50% austenite after proper solution annealing. Key alloying elements including chromium, molybdenum, nitrogen, tungsten, and copper contribute to the high pitting resistance equivalent number (PREN > 40), ensuring exceptional corrosion resistance.
| Element | Specification Range (%) | Remarks |
|---|---|---|
| Carbon (C) | 0.03 max | |
| Manganese (Mn) | 1.5 max | |
| Silicon (Si) | 0.8 max | |
| Phosphorus (P) | 0.035 max | |
| Sulfur (S) | 0.020 max | |
| Chromium (Cr) | 24.0 – 26.0 | Key element for corrosion resistance |
| Nickel (Ni) | 6.0 – 8.0 | Austenite stabilizer |
| Molybdenum (Mo) | 3.0 – 4.0 | Enhances pitting resistance |
| Nitrogen (N) | 0.20 – 0.30 | Increases strength and pitting resistance |
| Copper (Cu) | 0.5 – 2.0 | Improves corrosion resistance in reducing acids |
| Tungsten (W) | 0.5 – 1.0 | Enhances pitting/crevice corrosion resistance |
| Iron (Fe) | Balance |
Super Duplex Stainless Steel ASTM A789 S32520 Pipe Thermal and Electrical Physical Properties
The following physical properties are typical reference values for solution-annealed S32520 super duplex stainless steel. Actual values may be influenced by processing history and test temperature. These data are useful for design calculations involving thermal expansion, heat transfer, and electrical conductivity.
| Property | Typical Value | Unit | Test Condition / Remarks |
|---|---|---|---|
| Density (ρ) | 7.8 | g/cm³ | Room temperature |
| Modulus of Elasticity (E) | 200 | GPa | Tension, room temperature |
| Shear Modulus (G) | 77 | GPa | Calculated from E and Poisson's ratio |
| Poisson's Ratio (ν) | 0.3 | - | Room temperature |
| Thermal Expansion Coefficient (α) | 13.0 | 10⁻⁶/K | 20 – 100 °C (68 – 212 °F) |
| Thermal Expansion Coefficient (α) | 13.5 | 10⁻⁶/K | 20 – 200 °C (68 – 392 °F) |
| Thermal Expansion Coefficient (α) | 14.0 | 10⁻⁶/K | 20 – 400 °C (68 – 752 °F) |
| Thermal Conductivity (λ) | 15 | W/m·K | At 20 °C |
| Thermal Conductivity (λ) | 17 | W/m·K | At 100 °C |
| Thermal Conductivity (λ) | 20 | W/m·K | At 300 °C |
| Specific Heat Capacity | 500 | J/kg·K | Room temperature |
| Electrical Resistivity (ρ_e) | 0.80 | μΩ·m | Room temperature |
Super Duplex Stainless Steel ASTM A789 S32520 Pipe Mechanical Properties
The mechanical properties below reflect the minimum values required by ASTM A789/A789M for S32520 at room temperature. Actual properties may vary depending on product form, wall thickness, and heat treatment. The high strength of this grade allows for lighter designs compared to conventional austenitic stainless steels. Hardness testing is also commonly performed.
| Property | Minimum Required Value | Unit | Testing Condition / Remarks |
|---|---|---|---|
| Tensile Strength (Rm) | 800 | MPa | Room temperature, per ASTM A370 |
| Tensile Strength (Rm) | 116 | ksi | Room temperature, per ASTM A370 |
| Yield Strength (ReH, 0.2% offset) | 550 | MPa | Room temperature, per ASTM A370 |
| Yield Strength (ReH, 0.2% offset) | 80 | ksi | Room temperature, per ASTM A370 |
| Elongation after fracture (A) | 15 | % | In 50 mm (2 in.) gauge length; for wall thickness ≤ 5/16 in. (7.94 mm). For thinner walls, elongation requirements may differ. |
| Hardness (Rockwell C) | 32 max | HRC | Typical maximum in solution-annealed condition, not always mandatory in A789 for all sizes |
| Bend Test | No cracks | - | 180-degree bend; bend radius dependent on tube outside diameter per ASTM A789; usually acceptable when no evidence of cracks after bending. |
Super Duplex Stainless Steel ASTM A789 S32520 Pipe Full Equivalent Material Standards & Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10088-3 / EN 10216-5 | X2CrNiMoCuWN 25-7-4 (1.4501) | Closest European equivalent; often considered identical in composition and properties. Widely used for tubes and pipes. |
| USA | ASTM A790 / A790M | S32520 | Pipe specification for duplex stainless steels; equivalent grade for pipe forms, not just tube. |
| USA | ASTM A182/A182M | F61 | Forging equivalent to S32520 (UNS S32520) for flanges and fittings. |
| USA | ASME SA-789/SA-789M | S32520 | ASME Boiler and Pressure Vessel Code adoption of ASTM A789. |
| International | ISO 9327-5 | X2CrNiMoCuWN 25-7-4 | ISO standard harmonized with EN 1.4501. |
| International | NACE MR0175 / ISO 15156-3 | UNS S32520 | Listed for sour service applications in petroleum and natural gas industries. |
Super Duplex Stainless Steel ASTM A789 S32520 Pipe Application Introduction
ASTM A789 S32520 pipes and tubes are engineered for demanding environments where both high mechanical loads and severe corrosive conditions exist. The grade's excellent resistance to chloride-induced stress corrosion cracking and pitting makes it ideal for seawater and chemical processing. Typical component forms include seamless and welded pipes, heat exchanger tubes, and instrumentation tubing.
Product Applications: Seamless and welded heat exchanger tubes, Hydraulic and instrumentation tubing, Offshore risers and flowlines, High-pressure piping for desalination plants, Chemical injection quills, Umbilicals and subsea control lines, Boiler tubes for aggressive environments
Processed into products: Tube bundles for shell-and-tube heat exchangers, Corrosion-resistant liners and spools, Valve components and pump shafts (when forged or machined from bar stock), Fittings and flanges (when made from ASTM A789 pipe or A182 F61), Welded pipe spools for topside and subsea systems, Instrumentation and bleed rings
Application industries: Oil & Gas (offshore topside piping, subsea flowlines, downhole tubing, hydraulic and control lines), Chemical & Petrochemical (reactors, coolers, piping in contact with aggressive acids), Marine & Shipbuilding (seawater cooling systems, firefighting piping, desalination units), Desalination (reverse osmosis high-pressure piping, evaporator tubes), Pulp & Paper (bleach plant washers, digesters, corrosive chemical handling), Flue Gas Desulfurization (absorber vessels, chimney liners), Power Generation (heat exchanger tubing for nuclear, fossil, and renewable plants)
Super Duplex Stainless Steel ASTM A789 S32520 Pipe Similar / Comparable Alternative Materials
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| USA | ASTM A789 | S32760 | Super duplex stainless steel with similar chromium, nickel, molybdenum, and additional tungsten/copper. Often considered a direct substitute, but verify exact composition and mechanical requirements. |
| Europe | EN 10216-5 | X2CrNiMoCuWN 25-7-4 (1.4501) | Actually the direct European equivalent of S32520, but often listed here as it is the same alloy family. Some datasheets treat S32760 (ASTM) and 1.4501 as interchangeable, though UNS numbers differ. |
| USA | ASTM A789 | S32750 | Super duplex stainless steel (2507) without tungsten and with lower copper. Provides similar strength and corrosion resistance but may have slightly lower resistance in certain environments. Possible alternative where hydrogen sulfide is a concern. |
| Europe | EN 10216-5 | X2CrNiMoN 25-7-4 (1.4410) | 200-series nitrogen-alloyed super duplex, comparable to S32750. Lacks intentional tungsten/copper additions, thus PREN may be slightly lower. Suitable for many aggressive media but not a full substitute in all cases. |
Notes:
Heat treatment: Material shall be supplied in the solution-annealed condition. The recommended solution annealing temperature is typically 1020–1100 °C (1870–2010 °F) followed by rapid water quenching or air cooling to avoid the formation of detrimental intermetallic phases. Welding: Welding should be carried out with matching or over-matching filler metals (e.g., ER2594 or similar super duplex filler). Post-weld heat treatment is generally not required for thin-wall tube assemblies if proper welding procedures are followed, but may be necessary for heavy sections. Testing: In addition to standard tensile and flattening tests, corrosion testing according to ASTM G48 Method A or E is often specified to verify pitting and crevice corrosion resistance. Certification: Full compliance with ASTM A789/A789M requires a material test report (MTR) showing chemical analysis, tensile properties, and supplementary tests as agreed upon.
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