ASTM A789 S39274 Super Duplex Stainless Steel Pipe
ASTM A789 S39274 Super Duplex Stainless Steel Pipe - High Strength & Corrosion Resistance
Explore the chemical composition, mechanical properties, and physical properties of ASTM A789 S39274 super duplex stainless steel pipe, ideal for demanding chloride-containing environments.
Hot working, cold working, welding (with appropriate filler), machining, forming
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ASTM A789 S39274 Super Duplex Stainless Steel Pipe Introduction
ASTM A789 S39274 is a super duplex stainless steel tube grade defined in ASTM A789/A789M standard for seamless and welded ferritic/austenitic stainless steel tubing for general service. UNS S39274 is a tungsten-modified duplex alloy offering superior corrosion resistance, particularly in seawater and chloride-bearing environments, combined with high mechanical strength. Its balanced microstructure provides excellent resistance to stress corrosion cracking, pitting, and crevice corrosion, making it suitable for chemical processing, oil and gas, and marine applications. The typical microstructure consists of approximately equal volumes of austenite and ferrite, delivering high strength while maintaining adequate ductility. The grade is typically supplied in the solution-annealed and quenched condition.
ASTM A789 S39274 Super Duplex Stainless Steel Pipe Chemical Composition
The chemical composition of UNS S39274 as per ASTM A789/A789M is strictly controlled to achieve the desired duplex microstructure and corrosion resistance. The following table lists the specified maximum or range limits for each element. Tungsten is intentionally added to enhance pitting resistance and strength. The balance is iron (Fe).
| Chemical Element | Standard Value (wt.%) | Remarks |
|---|---|---|
| Carbon (C) | ≤ 0.030 | Maximum |
| Manganese (Mn) | ≤ 1.00 | Maximum |
| Silicon (Si) | ≤ 0.80 | Maximum |
| Phosphorus (P) | ≤ 0.035 | Maximum |
| Sulfur (S) | ≤ 0.020 | Maximum |
| Chromium (Cr) | 24.0 – 26.0 | Range |
| Nickel (Ni) | 6.0 – 8.0 | Range |
| Molybdenum (Mo) | 2.5 – 3.5 | Range |
| Nitrogen (N) | 0.24 – 0.32 | Range |
| Tungsten (W) | 0.8 – 1.5 | Range |
ASTM A789 S39274 Super Duplex Stainless Steel Pipe Thermal and Electrical Physical Properties
The physical properties below are typical for super duplex stainless steel UNS S39274 in the solution-annealed condition. These data are representative of published manufacturer data and materials science sources. Actual values may vary slightly depending on exact composition and production route.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.8 | g/cm³ | Room temperature |
| Elastic Modulus (E) | 200 | GPa | Room temperature, tension |
| Shear Modulus (G) | 77 | GPa | Room temperature |
| Poisson's Ratio (ν) | 0.31 | – | Room temperature |
| Thermal Expansion Coefficient (α) | 13.0 | 10⁻⁶ /K | 20–100 °C |
| Thermal Expansion Coefficient (α) | 13.5 | 10⁻⁶ /K | 20–200 °C |
| Thermal Expansion Coefficient (α) | 14.0 | 10⁻⁶ /K | 20–300 °C |
| Thermal Conductivity (λ) | 15 | W/m·K | 20 °C |
| Thermal Conductivity (λ) | 17 | W/m·K | 100 °C |
| Thermal Conductivity (λ) | 19 | W/m·K | 200 °C |
| Specific Heat Capacity | 500 | J/kg·K | 20°C |
| Electrical Resistivity (ρ_e) | 0.80 | μΩ·m | 20 °C |
ASTM A789 S39274 Super Duplex Stainless Steel Pipe Mechanical Properties
The mechanical properties below are the minimum requirements for ASTM A789 S39274 tubing in the solution-annealed condition at room temperature. These values are derived from the ASTM A789 standard and ensure the material's suitability for high-pressure and corrosive service. Hardness values are typically tested to verify proper heat treatment.
| Property | Standard Requirement | Unit | Test Conditions |
|---|---|---|---|
| Tensile Strength (Rm) | ≥ 725 | MPa | Room temperature, longitudinal specimen |
| Yield Strength (ReH, 0.2% offset) | ≥ 550 | MPa | Room temperature, longitudinal specimen |
| Elongation (A) | ≥ 25 | % | In 50 mm (2 in.) gauge length, all wall thicknesses |
| Hardness | ≤ 32 HRC / ≤ 290 HBW | – | At room temperature, as per ASTM E18/ASTM E10 |
ASTM A789 S39274 Super Duplex Stainless Steel Pipe Identical Material Standards and Substitutable Grades
Grade S39274 is uniquely defined by UNS S39274. While the composition is occasionally produced under other national standards, the authoritative designation remains ASTM A789/ASME SA789. The following table lists the standardised fully equivalent grades.
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| USA | ASTM A789/A789M | S39274 (UNS S39274) | Seamless and welded tubes, identical composition and properties |
| USA | ASME SA789/SA789M | S39274 | ASME Boiler and Pressure Vessel Code identical to ASTM A789 |
ASTM A789 S39274 Super Duplex Stainless Steel Pipe Application Introduction
Due to its high strength and exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking in chloride environments, ASTM A789 S39274 tubing is well suited for a variety of demanding applications. The sections below summarise typical industries, products, and specific components.
Product Applications: Seamless and welded stainless steel tubes, Pipe spools and fittings, Umbilicals and hydraulic control lines, Heat exchanger tube bundles, Process piping in corrosive service
Processed into products: Heat exchanger tubes, Subsea umbilical tubing, Seawater cooling pipes, Injection lines in oil recovery, Hydraulic tubing for corrosive fluids, Condenser tubes in power plants, Desalination brine heater tubes, Process instrumentation tubing
Application industries: Oil and Gas (upstream and downstream), Chemical and petrochemical processing, Seawater and marine systems, Desalination plants, Heat exchanger manufacturing, Pulp and paper industry, Power generation (condenser tubing), Hydraulic and instrumentation systems
ASTM A789 S39274 Super Duplex Stainless Steel Pipe Similar / Alternative Super Duplex Stainless Steel Grades
The following super duplex stainless steels are not identical but share comparable corrosion resistance and mechanical strength. They can be considered as substitutes in many applications, subject to engineering assessment of their specific composition differences and resulting properties.
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| USA | ASTM A789/A789M | S32750 (UNS S32750) | SAF 2507, Cr-Ni-Mo-N super duplex, no tungsten |
| USA | ASTM A789/A789M | S32760 (UNS S32760) | Zeron 100, contains W and Cu, similar pitting resistance |
| Europe | EN 10216-5 / EN 10217-7 | 1.4410 (X2CrNiMoN25-7-4) | Corresponds to UNS S32750, similar but no intentional W |
| Europe | EN 10216-5 / EN 10217-7 | 1.4501 (X2CrNiMoCuWN25-7-4) | Similar to UNS S32760, W and Cu bearing |
| USA | ASTM A789/A789M | S32550 (UNS S32550) | 255, lower molybdenum, older super duplex grade |
Notes:
Delivery condition is typically solution annealed at 1080–1120°C (1975–2050°F) followed by rapid water quenching. Optional supplementary tests such as ultrasonic testing, eddy current testing, and impact testing may be specified in the purchase order. The material can be welded using common methods (e.g., GTAW, GMAW, SAW) with appropriate over-alloyed fillers (e.g., 25.10.4.L or similar). Post-weld heat treatment is generally not required for thin sections, but full solution annealing may be specified for critical applications. Data provided are for reference; always consult the latest edition of the relevant ASTM standard and the material test certificate for the specific product.
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