Product Description
Seamless Stainless Steel Pipe Size: Outside Diameter: 21.3mm – 914mm (1/2″ – 36″), Wall Thickness: 0.5mm – 50mm (Schedule 5S, 10S, 40S, 80S, 160, XXS), Length: 6m – 12m standard, custom lengths up to 18m
Standard & Grade of Seamless Stainless Steel Pipe: ASTM A312 TP316, TP316L; also ASME SA312; EN 10216-5 1.4401, 1.4404; Equivalent to AISI 316, 316L; JIS G3459 SUS316TP, SUS316LTP
Usage of Seamless Stainless Steel Pipe: Marine and offshore platforms (seawater cooling, firewater, ballast lines), chemical and petrochemical plants (chlorides, organic acids), pharmaceutical manufacturing (WFI, purified water), food processing (high chloride environments), pulp and paper bleach plants, heat exchangers and condensers, desalination plants, oil and gas processing (sour service with chlorides), textile dyeing equipment, architectural coastal structures, high-pressure hydraulic lines, cryogenic service
Womic Steel offering high quality & competitive prices of ASTM A312 TP316/316L seamless stainless steel pipe, SMLS stainless pipe, cold drawn seamless tube, seamless 316 pipe, marine grade stainless seamless pipe, high-pressure seamless pipe. Mill certificate EN 10204 3.1/3.2, hydro test, UT/ET, solution annealed, beveled/plain ends, pickled/polished/electropolished finish available. Factory direct supply for marine, chemical, and high-purity projects worldwide.
Womic Steel: Manufacturing Capabilities & Company Strength
Womic Steel Group is a premier manufacturer and global exporter with over 20 years of expertise in producing carbon, alloy, and stainless steel tubular products. Our state-of-the-art seamless pipe production facility specializes in super duplex stainless steel seamless pipes for the most demanding offshore and chemical applications.
Production Size Range for ASTM A789/A790 2507 Super Duplex Seamless Pipe: Outside diameter from 6.0mm to 610mm (1/8 inch to 24 inch) with wall thickness from 0.5mm to 50.0mm . Single random lengths of 6m, double random lengths of 12m, or custom lengths up to 18m as required. Available in both seamless (A789/A790) and welded configurations .
Quality Certifications & Regulatory Compliance:
ISO 9001:2015 Certified: Quality management system ensuring consistent product quality across all operations.
ASTM A789/A790 Compliance: Full compliance with ASTM A789 (small diameter tubing) and ASTM A790 (large diameter pipe) for super duplex stainless steel. A789 covers tubing for general service, A790 covers pipe for corrosive service with emphasis on stress corrosion cracking resistance .
PED 2014/68/EU (CE Marking): Compliance with European Pressure Equipment Directive. CE marking available upon request .
NACE MR0175 / ISO 15156: Certification available for sour service applications requiring H₂S resistance.
EN 10204 3.2 Certification: Inspection Certificate 3.2 validated by TÜV, LR, BV, or SGS for critical applications requiring full material traceability.
EN 10216-5 Compliance: Available for European market requirements .
Third-Party Inspection (TPI) Approvals: Products approved by DNV, BV, ABS, LR, SGS, TÜV.
Global Recognition: Trusted supplier to offshore EPC contractors, subsea system manufacturers, chemical plants, and desalination companies serving over 80 countries worldwide.
ASTM A789/A790 2507 Super Duplex Stainless Steel Seamless Pipe: Material Composition & Performance Characteristics
ASTM A789/A790 2507 is a super duplex (austenitic-ferritic) stainless steel with a microstructure consisting of approximately 50% austenite and 50% ferrite . The "super duplex" designation indicates higher alloy content than standard duplex (2205), providing exceptional corrosion resistance and mechanical strength.
Key Designations:
UNS: S32750
EN Number: 1.4410
EN Name: X2CrNiMoN 25-7-4
Trade Name: SAF 2507 (Alleima), F53
Compared to standard duplex 2205 (PREN 34-38), 2507 offers a PREN (Pitting Resistance Equivalent Number) >40, providing superior pitting and crevice corrosion resistance . Yield strength exceeds 550 MPa (80,000 psi) – more than double that of 316L (170 MPa) .
ASTM A789/A790 2507 Super Duplex Chemical Composition (Ladle Analysis, % by mass):
| Element | UNS S32750 Requirement (SAF 2507 / 1.4410) |
| Carbon (C) | ≤ 0.030 |
| Silicon (Si) | ≤ 0.80 |
| Manganese (Mn) | ≤ 1.20 |
| Phosphorus (P) | ≤ 0.035 |
| Sulfur (S) | ≤ 0.020 |
| Chromium (Cr) | 24.0 - 26.0 |
| Nickel (Ni) | 6.0 - 8.0 |
| Molybdenum (Mo) | 3.0 - 5.0 |
| Nitrogen (N) | 0.24 - 0.32 |
| Copper (Cu) | ≤ 0.50 |
| Iron (Fe) | Balance |
*Note: High chromium (24-26%), molybdenum (3-5%), and nitrogen (0.24-0.32%) provide exceptional pitting and crevice corrosion resistance. The duplex structure (austenite+ferrite) offers high strength and excellent resistance to chloride stress corrosion cracking .*
ASTM A789/A790 2507 Super Duplex Mechanical Properties (Room Temperature):
| Property | UNS S32750 Requirement |
| Yield Strength (min, 0.2% offset) | 550 MPa (80,000 psi) |
| Tensile Strength (min) | 800 MPa (116,000 psi) |
| Elongation (min) | 25% |
| Hardness (max) | 28 HRC / 290 HV |
ASTM A789/A790 2507 Super Duplex Physical Properties:
| Property | Value |
| Density | 7.8 g/cm³ |
| Melting Point | 1350-1400°C |
| Modulus of Elasticity | 200 GPa |
| Thermal Conductivity (20°C) | 19 W/m·K |
| Electrical Resistivity | 80 μΩ·cm |
| Coefficient of Thermal Expansion (20-200°C) | 13.7 μm/m·K |
Corrosion Resistance Properties (PREN Comparison):
| Grade | PREN Value | Yield Strength | Key Characteristic |
| 316L | 24-26 | 170 MPa | General corrosion resistance |
| 904L | 33 | 220 MPa | High acid resistance |
| 2205 (Duplex) | 34-38 | 450 MPa | Balanced duplex, general marine |
| 2507 (Super Duplex) | >40 | 550 MPa | Maximum corrosion & strength |
| S32760 (Super Duplex) | >40 | 550 MPa | With tungsten addition |
*Note: PREN = Cr + 3.3(Mo) + 16(N). 2507's PREN >40 provides exceptional resistance to pitting and crevice corrosion in high chloride environments .*
Temperature Limitations:
| Parameter | Limit |
| Maximum Continuous Service | 300°C (570°F) |
| Minimum Service Temperature | -50°C (-58°F) |
| Recommended Range | -50°C to 300°C |
*Note: 2507 is not recommended for temperatures below -50°C or above 300°C, as toughness decreases outside this range .*
Grade Comparison – 2507 vs 2205 vs 316L:
| Property | 316L | 2205 Duplex | 2507 Super Duplex |
| Yield Strength (MPa) | 170 | 450 | 550 (+23% vs 2205) |
| PREN | 24-26 | 34-38 | >40 |
| Critical Pitting Temp (°C) | 15-25 | 50-60 | 70-80 |
| Chloride SCC Resistance | Moderate | Excellent | Excellent |
| Typical Application | General service | Offshore, marine | Deep water, extreme conditions |
Key Performance Advantages:
Excellent resistance to stress corrosion cracking (SCC) in chloride-bearing environments
Excellent resistance to pitting and crevice corrosion (PREN >40)
High resistance to general corrosion
Very high mechanical strength (550 MPa yield)
High resistance to erosion corrosion and corrosion fatigue
Good weldability with proper procedures
ASTM A789/A790 2507 Super Duplex Stainless Steel Seamless Pipe Dimensional Range & Standards Compliance
Womic Steel supplies ASTM A789/A790 2507 super duplex seamless pipes across a wide dimensional spectrum, fully compliant with ASTM A789 and ASTM A790 standards .
Key Standard Distinction:
ASTM A789: Covers tubing for general service applications – smaller diameter tubes for heat exchangers, condensers, and fluid conveyance
ASTM A790: Covers pipe for general corrosive service – larger diameter pipes for fluid transport lines, pipelines, and applications emphasizing SCC resistance
| Item | Specification |
| Standard | ASTM A789 (Seamless tubing, OD ≤ 5"), ASTM A790 (Seamless pipe, OD ≥ 1/8") |
| Grade | UNS S32750 (2507, SAF 2507, 1.4410, F53, X2CrNiMoN25-7-4) |
| Also Available | UNS S32760 (1.4501, F55, Zeron 100) |
| Manufacturing Process | Seamless - Cold Drawn / Cold Rolled / Extrusion |
| Outside Diameter Range | 6.0mm – 610mm (1/8" – 24") |
| Wall Thickness Range | 0.5mm – 50.0mm |
| Length | 6m (SR), 12m (DR), or custom lengths up to 18m; coils available for small diameters |
| Delivery Condition | Solution annealed (1040-1120°C) + water quenched |
| End Finish | Plain End (PE) / Beveled End (BE) |
| Surface Finish | Annealed & Pickled / Bright Annealed (BA) / Polished |
| Schedules | Sch 5S, 10S, 40S, 80S, 10, 20, 30...120, 140, 160, XXS |
| Microstructure | 40-60% ferrite / 60-40% austenite |
Dimensional Tolerances per ASTM A789/A790:
| Characteristic | Tolerance |
| OD < 1.5" (38.1mm) | ±0.005" (±0.13mm) |
| OD 1.5" - 3" (38.1-76.2mm) | ±0.010" (±0.25mm) |
| OD 3.5" - 4" (88.9-101.6mm) | ±0.015" (±0.38mm) |
| OD > 4" (101.6mm) | ±1.0% |
| Wall Thickness (WT) | ±10% |
| Length (mill length) | +50mm, -0mm |
| Precision length cuts | +3mm, -0mm |
Available Product Forms:
Seamless Pipe (A790)
Seamless Tube (A789)
Coiled Tubing (capillary tubes for subsea umbilicals)
U-Bend Tubes for heat exchangers
Square and Rectangular Tubes
Manufacturing Process – Stainless Steel Seamless Tube
Womic Steel produces ASTM A213 TP321 stainless steel seamless tubes using advanced cold drawing and cold rolling processes, ensuring precise dimensional tolerances and superior surface finish.
Production Workflow (Cold Drawn / Cold Rolled Seamless Tube Process):
Raw Material Inspection (Billet): Incoming stainless steel round billets (typically 50-200mm diameter) are verified for chemical composition per ASTM A213 TP321 requirements (17-19% Cr, 9-12% Ni, Ti ≥ 5×C). Each billet is assigned a unique heat number for full material traceability throughout production.
Billet Heating & Piercing: Billets are heated to forging temperature (1150-1250°C) in rotary hearth furnaces and pierced via cross-roll piercing mill (Mannesmann process) to form hollow tube shells (hollow blooms).
Extrusion or Rolling: The pierced hollow shells undergo further hot rolling or extrusion to reduce diameter and wall thickness. For TP321, careful temperature control prevents titanium carbide precipitation during hot working.
Annealing (Intermediate): After hot working, tubes are solution annealed at 1040-1120°C followed by rapid cooling (water quenching or air cooling) to dissolve carbides and restore corrosion resistance.
Pickling & Descaling: Scale formed during annealing is removed by pickling in acid baths (nitric-hydrofluoric acid mixture), revealing a clean, uniform surface.
Cold Drawing (Single or Multiple Passes): Tubes undergo single or multiple cold drawing passes through precision dies and over mandrels to achieve required OD, WT, and dimensional tolerances. Typical reduction per pass: 20-40%.
Cold Rolling (Pilgering - Optional): For greater wall thickness reduction or improved surface finish, tubes are processed through cold pilger mills. This process is particularly effective for thin-wall and precision tubes.
Intermediate Annealing: Between drawing or rolling passes, tubes undergo intermediate annealing (1040-1120°C) to relieve work hardening and restore ductility for subsequent processing.
Final Heat Treatment (Solution Annealing): Tubes receive final solution annealing at 1040-1120°C followed by rapid cooling to achieve specified mechanical properties, corrosion resistance, and grain structure. This is critical for TP321 to ensure titanium carbides are properly dissolved and reprecipitated.
Straightening & Cutting: Precision straightening to meet standard straightness tolerances (0.15% of total length), followed by cutting to exact ordered lengths with clean, burr-free ends.
Finishing & Surface Inspection: Visual examination to ensure freedom from surface defects such as cracks, folds, laps, and scabs. Pickling or bright annealing applied as final surface finish.
End Finishing: Plain ends (square cut), beveled ends (30-35° bevel angle with 1.6mm ±0.8mm landing), or threaded ends as per customer specification.
Quality Control & Testing Procedures
| Stage | Inspection Method | Purpose |
| Raw Material (Billet) | Chemical Analysis (OES Spectrometer) | Verify compliance with ASTM A213 TP321 composition limits (Cr, Ni, Ti, C, etc.) |
| Raw Material (Billet) | Tensile Testing at Room Temperature | Verify base material strength before processing |
| Raw Material (Billet) | Ultrasonic Testing (UT) | Detect internal laminations and defects |
| In-Process | Dimensional Inspection (Micrometers, Calipers) | Monitor OD, WT during drawing and rolling |
| In-Process | Surface Visual Inspection | Detect surface defects (folds, laps, cracks) |
| Finished Tube | Solution Annealing Verification | Ensure proper heat treatment (1040-1120°C, rapid cooling) |
| Finished Tube | Tensile Testing (Room & High Temp) | Verify yield strength (min 205 MPa), tensile strength (min 515 MPa), elongation (min 35%) |
| Finished Tube | Hardness Test (HRB / HV) | Verify maximum hardness 92 HRB / 210 HV |
| Finished Tube | Flaring Test | Verify ductility and soundness (tube end expanded with tapered mandrel) |
| Finished Tube | Flattening Test | Verify ductility and soundness (tube flattened between parallel plates) |
| Finished Tube | Hydrostatic Testing | Each tube pressure tested to specified pressure (no leakage permitted) |
| Finished Tube | Eddy Current Testing (ET) | Continuous on-line inspection for surface and subsurface defects |
| Finished Tube | Ultrasonic Testing (UT) | Full body inspection for internal defects (supplementary requirement) |
| Finished Tube | Intergranular Corrosion Test (Optional) | Verify resistance to sensitization (per ASTM A262 Practice E) |
| Finished Tube | Dimensional & Visual Inspection | Verify OD, WT, length, straightness, surface quality |
| Finished Tube | Marking Verification | Ensure permanent marking per ASTM A213 (standard, grade, size, heat number) |
Supplementary Tests (Upon Request):
High Temperature Tensile Test
Creep and Stress Rupture Test
Charpy Impact Test (for low temperature applications)
Grain Size Measurement (per ASTM E112)
Intergranular Corrosion Test per ASTM A262 (Practice E - Strauss test)
Ferrite Content Measurement (for duplex stainless steel)
Quality Documentation:
Mill Test Certificate per EN 10204 Type 3.1 or 3.2
Hydrostatic Test Report (tube-by-tube)
ET / UT Inspection Report
Flaring / Flattening Test Report
Traceability from heat number to finished tube
NACE MR0175 certification (upon request)
Primary Applications – ASTM A213 TP321 Stainless Steel Seamless Tube
ASTM A213 TP321 stainless steel seamless tubes are essential components in high temperature and corrosive service environments across various industries:
Power Generation: Superheater tubes, reheater tubes, boiler water wall tubes, steam headers, and main steam pipelines in thermal power plants, combined cycle units, and nuclear power plants (non-core). TP321's high temperature strength up to 816°C makes it ideal for supercritical boiler applications.
Industrial Boilers: Steam generation systems, hot water boilers, waste heat recovery boilers (WHRB), and heat recovery steam generators (HRSG) for manufacturing facilities. The titanium stabilization prevents sensitization during welding and service.
Petrochemical & Refining: Heat exchangers, process heaters, cracking furnaces (ethylene crackers), reformer tubes, and high temperature fluid transfer lines in refineries and petrochemical plants. TP321 resists polythionic acid stress corrosion cracking in refinery service.
Chemical Processing: Reactors, reformers, high temperature piping systems handling corrosive gases and liquids, and equipment for nitric acid, sulfuric acid, and organic chemical production.
High Temperature Headers: Steam headers and manifold systems operating at temperatures between 400-800°C where creep resistance and thermal stability are critical.
Furnace Tubes: Radiant tubes, convection section tubes, and transfer lines in industrial furnaces, thermal oxidizers, and incinerators.
Heat Exchangers: Shell and tube heat exchangers, U-tube bundles, and condenser tubes for high temperature and corrosive service.
Aerospace & Defense: High temperature hydraulic lines, engine bleed air systems, and exhaust system components requiring oxidation resistance up to 800°C.
Pharmaceutical & Food Processing: High temperature steam lines and sterile processing equipment where corrosion resistance and cleanability are essential.
Common International Standards for Stainless Steel Seamless Tubes
| Standard | Full Standard Name | Applicable Grades | Typical Application |
| ASTM A213 | Standard Specification for Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes | TP304, TP304L, TP304H, TP309, TP310, TP316, TP316L, TP316H, TP316Ti, TP321, TP321H, TP347, TP347H | Boiler tubes, superheater tubes, heat exchanger tubes |
| ASTM A312 | Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes | TP304/L, TP316/L, TP321, TP347, TP904L | General service stainless steel pipes, pressure piping |
| ASTM A269 | Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubes for General Service | TP304/L, TP316/L, TP321, TP347 | General service tubing, instrumentation, mechanical applications |
| ASTM A789 | Standard Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing for General Service | S31803 (2205), S32205, S32750 (2507), S32760 | Duplex stainless steel tubes, general service |
| ASTM A790 | Standard Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe | S31803 (2205), S32205, S32750 (2507), S32760 | Duplex stainless steel pipes, pressure applications |
| EN 10216-5 | Seamless steel tubes for pressure purposes - Technical delivery conditions - Part 5: Stainless steel tubes | 1.4301 (304), 1.4307 (304L), 1.4401 (316), 1.4404 (316L), 1.4541 (321), 1.4878 (321H), 1.4550 (347) | Pressure purposes, European market |
| EN 10305-1 | Steel tubes for precision applications - Technical delivery conditions - Part 1: Seamless cold drawn tubes | E215, E235, E355 (carbon steel) | Precision applications, hydraulic cylinders |
| EN 10216-2 | Seamless steel tubes for pressure purposes - Non-alloy and alloy steel tubes with specified elevated temperature properties | P235GH, P265GH, P295GH, P355GH (carbon/alloy) | Pressure purposes, elevated temperature |
| JIS G3459 | Stainless steel pipes | SUS304TP, SUS304LTP, SUS316TP, SUS316LTP, SUS321TP, SUS347TP | Stainless steel pipes, Japanese market |
| JIS G3463 | Stainless steel boiler and heat exchanger tubes | SUS304TKA, SUS316TKA, SUS321TKA, SUS347TKA | Boiler and heat exchanger tubes, Japanese market |
| GB/T 14976 | Seamless stainless steel pipes for fluid transport | 0Cr18Ni9 (304), 00Cr17Ni14Mo2 (316L), 1Cr18Ni9Ti (321) | Fluid transport, Chinese market |
| GB/T 14975 | Seamless stainless steel pipes for structural purposes | 0Cr18Ni9 (304), 1Cr18Ni9Ti (321) | Structural purposes, Chinese market |
| GB 13296 | Seamless stainless steel tubes for boiler and heat exchanger | 0Cr18Ni9 (304), 0Cr17Ni12Mo2 (316), 1Cr18Ni9Ti (321) | Boiler and heat exchanger, Chinese market |
| ISO 1127 | Stainless steel tubes - Dimensions, tolerances and conventional masses per unit length | — | Dimensional standard for stainless steel tubes |
| NACE MR0175 / ISO 15156 | Petroleum and natural gas industries - Materials for use in H₂S-containing environments in oil and gas production | 304/L, 316/L, 321, 347, 2205, 2507 | Sour service, oil and gas production |
Packaging & Shipping
Packaging:
Protective Covering: Individual plastic sleeves or spiral wrapping applied to each tube to prevent surface scratches and moisture contact.
Bundling: Tubes bundled together and secured with steel straps (3-5 straps per bundle) with protective corner guards. Wooden dunnage or foam rings between layers prevents abrasion.
End Caps: Plastic end caps (PE or PP) on both ends protect beveled/plain ends and threads from impact damage and debris ingress.
Wooden Crates: For high-value or precision orders, tubes packed in sturdy wooden crates or plywood cases for enhanced protection.
Desiccant Bags: Added for moisture-sensitive applications or long sea freight.
Shipping:
Mode of Transportation: Container vessels (20ft/40ft), bulk carriers (>500 tons), or air freight for sample shipments.
Containerization: Tubes loaded into standard containers. Max load: 20-25 tons per 20ft, 25-28 tons per 40ft.
Bulk Vessel Loading: Large orders loaded directly into bulk carriers with lifting beams, dunnage, and lashing to secure cargo.
Labeling & Documentation: Each bundle labeled with grade, standard, dimensions, heat number. Complete shipping documents (invoice, packing list, bill of lading, COO, MTC) prepared for customs clearance.
Secure Fastening: Bundles secured with steel strapping, dunnage bags, or timber bracing to prevent shifting during transit.
Tracking & Insurance: Container tracking numbers provided. Marine cargo insurance available upon request.
Common Industry Applications Summary
| Industry | Application | Recommended Grade |
| Power Generation | Superheater tubes, reheater tubes, boiler water walls, steam headers | TP321, TP321H, TP347H |
| Petrochemical | Ethylene cracking furnace tubes, reformer tubes, heat exchangers | TP321, TP321H, TP347 |
| Oil & Gas | High temperature piping, heat exchanger bundles, process heaters | TP321, TP316/L, 2205 |
| Chemical Processing | Reactors, high temperature piping, corrosive service | TP321, TP316/L, 904L |
| Pharmaceutical | High purity steam lines, sterile processing equipment | TP304/L, TP316/L (BA finish) |
| Food & Beverage | Processing equipment, high temperature steam lines | TP304/L, TP316/L (BA finish) |
| Refining | Crude heaters, vacuum heaters, catalytic crackers | TP321H, TP347H |
| Aerospace | High temperature hydraulic lines, exhaust systems | TP321, 17-4PH |
| Desalination | High temperature brine heaters, evaporators | TP316/L, 2205, 2507 |
| Pulp & Paper | Digester tubes, bleach plant piping, recovery boilers | TP316/L, 2205, 904L |
Womic Steel Advantages & FAQ
Why Partner with Womic Steel for Stainless Steel Seamless Tubes?
Complete Range of Grades: Full portfolio of austenitic (304/304L, 316/316L, 321/321H, 347/347H, 310S), duplex (2205, 2507), and super austenitic (904L) stainless steel seamless tubes under one roof.
Multiple Standard Compliance: ASTM A213, A312, A269, A789, A790, EN 10216-5, EN 10305-1, GB/T 14976, JIS G3459, JIS G3463. One supplier for multiple market requirements.
Precision Manufacturing: Cold drawn and cold rolled (pilgered) processes ensuring tight dimensional tolerances (±0.05mm for precision tubes) and superior surface finish (BA, mirror, brushed).
Full Traceability: Each tube traceable from heat number to finished product with complete documentation.
Value-Added Services: End beveling (30-35°), plain end cutting, threading, plastic caps installation, and surface finishing (BA, pickled, polished, mirror) available in-house.
Quality Assurance: 100% hydrostatic testing, eddy current testing (ET), optional ultrasonic testing (UT), flaring and flattening tests performed on every tube.
Third-Party Inspection: Facilitation of inspections by DNV, BV, SGS, TÜV, ABS, LR. 3.2 certificates supplied upon request.
Global Logistics: Strategic partnership with freight forwarders for optimized container loading and cost-effective worldwide shipping.
Technical Support: Engineering team available for material selection, grade substitution, and application consulting.
Choose Womic Steel Group as your reliable partner for high-quality ASTM A213 TP321 stainless steel seamless tubes and unbeatable delivery performance for boiler, heat exchanger, and petrochemical projects worldwide. Welcome to inquire!
Website: www.womicsteel.com
Email: sales@womicsteel.com
Tel/WhatsApp/WeChat:
Victor: +86-15575100681
Jack: +86-18390957568
Frequently Asked Questions (FAQ)
Q: What is the difference between ASTM A789 and ASTM A790 for 2507?
A: ASTM A789 covers tubing for general service applications, typically smaller diameters (OD ≤ 5") used in heat exchangers, condensers, and fluid conveyance. ASTM A790 covers pipe for general corrosive service, typically larger diameters used for fluid transport lines, pipelines, and applications with emphasis on stress corrosion cracking resistance .
Q: What is the difference between UNS S32750 (2507) and UNS S32760?
A: Both are super duplex grades. S32750 (2507/1.4410/F53) contains 24-26% Cr, 6-8% Ni, 3-5% Mo, 0.24-0.32% N. S32760 (1.4501/F55/Zeron 100) contains similar levels plus 0.5-1.0% tungsten (W) and 0.5-1.0% copper (Cu), providing enhanced corrosion resistance in some aggressive environments .
Q: What is PREN and why is it important for 2507?
A: PREN (Pitting Resistance Equivalent Number) is calculated as PREN = Cr + 3.3(Mo) + 16(N). 2507 has PREN >40, compared to 24-26 for 316L and 34-38 for 2205. Higher PREN indicates better resistance to pitting and crevice corrosion in chloride-containing environments .
Q: What is the maximum operating temperature for 2507 super duplex?
A: 2507 is suitable for service up to 300°C (570°F). Above 300°C, embrittling intermetallic phases may precipitate. For temperatures below -50°C, impact testing is required as toughness decreases. Recommended service range: -50°C to 300°C .
Q: Is 2507 resistant to chloride stress corrosion cracking (SCC)?
A: Yes. 2507 offers excellent resistance to chloride SCC, which is a common failure mode for austenitic stainless steels (304, 316) in marine and chemical environments. This makes 2507 the preferred choice for offshore platforms, subsea systems, and seawater handling applications .
Q: What is the required ferrite content for 2507 super duplex pipe?
A: The microstructure should contain 40-60% ferrite (balance austenite). Ferrite content is measured by metallographic examination or ferritescope. Womic Steel provides ferrite content measurement on every lot.
Q: Can 2507 be welded? Any special requirements?
A: Yes, but requires careful control. Use super duplex-specific consumables (2507/2594 filler metal). Preheat not required but interpass temperature must be controlled (≤ 150°C). Heat input: 0.5-2.0 kJ/mm. Post-weld heat treatment not required. Overheating must be avoided to prevent intermetallic phase formation. Welding procedures must be qualified.
Q: What are the typical applications for 2507 super duplex pipes?
A: Offshore platforms (topside and subsea), subsea umbilicals (hydraulic and process fluid tubes), seawater cooling systems, desalination plants (reverse osmosis pressure vessels, seawater transport), chemical processing (organic acid plants), oil and gas production, heat exchangers, flue gas desulfurization systems, pulp and paper bleaching, propeller shafts, geothermal wells .
Q: What NDT is available for 2507 super duplex pipes?
A: 100% PMI (Positive Material Identification) for grade verification, hydrostatic testing (each pipe), ultrasonic testing (UT), eddy current testing (ET), ferrite content measurement, intermetallic phase detection, and optional supplementary requirements including impact testing and grain size determination .
Q: Can you provide third-party inspection for 2507 super duplex pipes?
A: Yes. Inspections by DNV, BV, SGS, TÜV, ABS, LR available. 3.2 inspection certificates and NACE MR0175 certification supplied upon request. Third-party witnessing of PMI, mechanical testing, NDT, and dimensional inspection available.
Q: What is the typical lead time for 2507 super duplex seamless pipes?
A: 30-45 days for standard sizes. 45-60 days for custom sizes. 2507 is a high-grade special order material with limited stock. Third-party inspection adds 10-15 days. NACE MR0175 certification adds 5-10 days.
Q: What documentation do you provide for 2507 super duplex pipe shipments?
A: Mill Test Certificate (EN 10204 Type 3.1 or 3.2), PMI test report (100% grade verification), ferrite content measurement report, hydrostatic test report, UT/ET report, tensile test report (room temperature), impact test report (if specified), NACE MR0175 certification (if required), dimensional report, packing list, invoice, bill of lading.
Q: What surface finishes are available for 2507 super duplex pipes?
A: Annealed and pickled (standard, removes scale and provides clean surface), bright annealed (BA - reflective surface with minimal scale), and mechanically polished (various grit finishes including No.4, HL, Mirror/8K) .
Q: Is 2507 suitable for subsea umbilical applications?
A: Yes. 2507 is widely used for subsea umbilical tubing (hydraulic and process fluid tubes) due to its high strength, excellent corrosion resistance in seawater, and good fatigue properties. Available in coiled form for long continuous lengths
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