2507 Seamless Super Duplex Steel Tube

UNS S32750 | 1.4410 | ASTM A789

2507 Seamless Super Duplex Steel Tube (S32750 / 1.4410) is manufactured to ASTM A789 from super duplex steel billet, cold-drawn to the required outside diameter and wall thickness. Supplied from our Wenzhou mill with EN 10204 3.1 mill test certificate, PMI and dimensional inspection on request.

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What Is a Seamless Super Duplex UNS S32750 Tube?

UNSS32750, also designated EN 1.4410 and commonly called 2507, is the reference super duplex stainless steel. Its 25% chromium, 4% molybdenum and high nitrogen content produce a PREN above 40 together with roughly twice the yield strength of standard austenitic grades, which allows thinner walls and lighter structures in high-pressure seawater and subsea duty.

2507 Key Features and Technical Advantages

The Seamless Super Duplex UNS S32750 Tube (EN 1.4410 / Super Duplex 2507) is a premium-grade stainless steel pipe designed for demanding applications involving high pressure, aggressive chloride environments, and critical fluid transmission systems.

Produced from a single solid billet through a seamless process, this tube eliminates weld seams, ensuring uniform mechanical properties, superior pressure resistance, and enhanced operational safety compared to welded alternatives.

UNS S32750 is a Super Duplex Stainless Steel (SDSS) with a balanced 50% austenite and 50% ferrite microstructure, combining the advantages of both phases—high strength and outstanding corrosion resistance.

Feature	Description
1. Exceptional Corrosion Resistance	Pitting corrosion Crevice corrosion Chloride Stress Corrosion Cracking (SCC)
2. High Strength & Lightweight Design	Reduced wall thickness Lower material weight Cost-efficient structural design
3. Excellent Toughness & Durability	Sub-zero temperatures Ambient and elevated temperatures
4. Seamless Structural Integrity	No weld seam defects No heat-affected zone (HAZ) Higher pressure ratings and reliability in critical systems

2507 Product Specifications and Data

UNS S32750 achieves its “Super Duplex” classification through a high-alloy composition:

Grade	C	Mn	P	S	Si	Ni	Cr	Mo	N	Cu	Others
31803	≤0.03	≤2.00	≤0.03	≤0.02	≤1.00	4.50-6.50	21.00-23.00	2.50-3.50	0.08-0.20	…	…
32205	≤0.03	≤2.00	≤0.03	≤0.02	≤1.00	4.50-6.50	22.00-23.00	3.00-3.50	0.14-0.20	…	…
31500	≤0.03	1.20-2.00	≤0.03	≤0.03	1.40-2.00	4.3-5.2	18.00-19.00	2.50-3.00	0.05-0.10	…	…
32550	≤0.04	≤1.50	≤0.04	≤0.03	≤1.00	4.50-6.50	24.00-27.00	2.90-3.90	0.10-0.25	1.50-2.50	…
32750	≤0.03	≤1.20	≤0.035	≤0.02	≤0.80	6.00-8.00	24.00-26.00	3.00-5.00	0.24-0.32	≤0.50	…
32760	≤0.03	≤1.00	≤0.030	≤0.01	≤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
32950	≤0.03	≤2.00	≤0.035	≤0.01	≤0.60	3.50-5.20	26.00-29.00	1.00-2.50	0.15-0.35	…	…
32906	≤0.03	0.80-1.50	≤0.030	≤0.03	≤0.50	5.80-7.50	28.00-30.00	1.50-2.60	0.30-0.40	≤0.80	…

NOTE: PREN:Cr+3.3*Mo+16*N≥41

UNS S32750 / 1.4410 is specifically designed to maintain its strength and shape in high-stress, corrosive environments.

Tensile Strength	Yield Strength	Elongation	Hardness
≥ 800 MPa	≥ 550 MPa	≥ 25%	≤ 290 HBW

Density	Melting Point	Thermal Expansion	Thermal Conductivity	Modulus of Elasticity	Electrical Resistivity
7.8 g/cm³	1450 °C approx.	13.5 µm/m·°C (20-100°C)	15.0 W/m·K (20°C)	200 GPa	0.85 x 10⁻⁶ Ω·m (20°C)

Specified Outside Diameter (OD) (Inches)	Permissible Variations in OD (± Inches)
1⁄2 to 1	±0.005
Over 1 to 1-1⁄2	±0.008
Over 1-1⁄2 to 2	±0.010
Over 2 to 2-1⁄2	±0.012
Over 2-1⁄2 to 3-1⁄2	±0.014
Over 3-1⁄2 to 5	±0.020

Specified Outside Diameter (OD) (Inches)	Specified Wall Thickness (WT) (Inches)	Permissible Variation (± Inches)
1⁄2 to 1 (Inclusive)	0.025 to 0.065(Inclusive)	±0.010
	Over 0.065to 0.134 (Inclusive)	±0.012
Over 1 to 1-1⁄2 (Inclusive)	0.025 to 0.065 (Inclusive)	±0.010
	Over 0.065 to 0.134 (Inclusive)	±0.012
Over 1-1⁄2 to 2 (Inclusive)	0.025 to 0.049 (Inclusive)	±0.011
	Over 0.049 to 0.083 (Inclusive)	±0.012
	Over 0.083 to 0.148 (Inclusive)	±0.014
Over 2 to 2-1⁄2 (Inclusive)	0.032 to 0.065 (Inclusive)	±0.013
	Over 0.065 to 0.109 (Inclusive)	±0.015
	Over 0.109 to 0.165 (Inclusive)	±0.017
Over 2-1⁄2 to 3-1⁄2 (Inclusive)	0.032 to 0.165 (Inclusive)	±0.020
	Over 0.165 to 0.220 (Inclusive)	±0.025
Over 3-1⁄2 to 5 (Inclusive)	0.083 to 0.165 (Inclusive)	±0.025
	Over 0.165 to 0.220 (Inclusive)	±0.030

2507 Dimensional Standards and Tolerances

S32750 super duplex seamless tubes are supplied to the dimensional tolerances of ASTM A789 / A1016 unless a tighter project specification applies.

For Specific Cut Lengths, the standard tolerance is +1⁄8 in. [3 mm], -0 in. [0 mm].

Important Note: The values presented here are based on the common tables in the ASTM A789 standard. The full specification, particularly the referenced ASTM A1016/A1016M (General Requirements for Ferritic Alloy Steel, Austenitic Alloy Steel, and Stainless Steel Tubes), contains other essential requirements like straightness and details for tubes with ODs outside of this range. Always consult the latest official standard for design and procurement.

2507 Common Industrial Applications

Industry	Typical Applications
Oil and Gas Industry	Subsea manifolds and flowlines Sour service piping High-pressure process equipment
Desalination Plants	RO high-pressure piping Brine handling systems Multi-stage flash evaporators
Chemical Processing	Reactors and heat exchangers Chloride-bearing process lines Acid handling equipment
Marine and Offshore Engineering	Seawater cooling systems Firewater and deluge piping Offshore platform pipework

2507 Quality Assurance and Production Process

Process Step	Description
Certification	All Super Duplex S32750 tubes are supplied to ASTM A789 / ASME SA789 and ASTM A790 / ASME SA790 with EN 10204 3.1 mill test certificates. Third-party inspection (SGS, BV, TUV, Lloyd's), PMI reports and full heat-number traceability can be provided on request.
Non-Destructive Testing (NDT)	Hydrostatic or eddy-current testing is performed on 100% of tubes. Ultrasonic testing (UT) and dye-penetrant inspection (PT) are available for critical service, with records retained for each production lot.
Material Verification	Positive Material Identification (PMI) and spectrometric analysis confirm that the chemical composition matches the ordered grade and that the ferrite/austenite balance is within the specified range.
Mechanical Testing	Tensile, yield, elongation and hardness tests are carried out per heat. Impact testing can be supplied at the project design temperature for subsea and low-temperature service.
Dimensional Inspection	Outside diameter, wall thickness, ovality and straightness are measured against ASTM A1016 / A1016M or ASTM A789 tolerances. Length, square-cut ends and end-finish conditions are verified before packing.

S32750 (2507) vs S32205 (2205) – Technical Comparison

S32750 super duplex and S32205 standard duplex are the two most common duplex choices. The selection usually turns on how aggressive the chloride environment is.

Chemical Composition and PREN

S32750: ~25% Cr, ~4% Mo, ~0.3% N — PREN above 40
S32205: ~22% Cr, ~3% Mo, ~0.17% N — PREN about 35
The higher alloy content of S32750 is what buys the additional margin

Corrosion Resistance

S32750 resists pitting and crevice attack at higher chloride concentrations and temperatures than S32205, and tolerates more aggressive sour service. Where S32205 is near its critical pitting temperature, S32750 typically still has margin.

Mechanical Strength

Both deliver roughly twice the yield strength of 316L. S32750 is usually slightly stronger, and its higher alloy content allows use at somewhat higher temperature before the austenite-ferrite balance becomes unfavourable.

Selection Guide

Choose S32750 for the most severe chloride service, high-temperature seawater and demanding subsea duty
Choose S32205 for the broad middle ground of chemical, oil and gas and desalination piping where it has decades of service experience
Confirm the critical pitting temperature of the actual service before deciding

Frequently Asked Questions About 2507 Seamless Super Duplex Steel Tubes

What is UNS S32750 super duplex tube?

UNS S32750, also designated EN 1.4410 and commonly called 2507, is the reference super duplex stainless steel. Its 25% chromium, 4% molybdenum and high nitrogen give a PREN above 40 together with roughly twice the yield strength of austenitic grades.

What is the difference between S32750 and S32205?

S32750 is a super duplex with PREN above 40; S32205 (2205) is a standard duplex with PREN about 35. S32750 resists pitting and crevice attack at higher chloride concentrations and temperatures and tolerates more aggressive sour service, at higher alloy cost.

What standard covers S32750 tube?

S32750 seamless tube is supplied to ASTM A789 / ASME SA789 for tubing and ASTM A790 / ASME SA790 for pipe, with dimensional tolerances per ASTM A1016 / A1016M.

What is S32750 tube used for?

S32750 is used for subsea manifolds and flowlines, sour service piping, reverse-osmosis high-pressure piping, desalination evaporators, and offshore seawater cooling systems.

Request a 2507 Tube Quotation

Send your Seamless Super Duplex UNS S32750 Tube enquiry with grade, application, size (OD and wall thickness or schedule), quantity, length, end finish and inspection requirements including any ferrite content limits or third-party witnessing.

Request an S32750 Tube Quotation