S32750 Super Duplex Stainless Steel Pipe

1. Exceptional Pitting and Crevice Corrosion Resistance: PRE ≥ 42 (minimum) due to high chromium (24–26%), molybdenum (3.0–5.0%), and nitrogen (0.24–0.32%) content, providing superior resistance in seawater, chlorides, and organic acids.

2. Superior Stress Corrosion Cracking Resistance: Excellent resistance to chloride-induced SCC, significantly outperforming 316L, 317L, and even standard 2205 duplex in high-temperature, high-chloride environments.

3. Ultra-High Mechanical Strength: Minimum yield strength of ≥ 550 MPa (approximately 2.5 times that of 316L), allowing for significant wall thickness reduction and weight savings in critical applications.

4. Excellent Low-Temperature Toughness: Maintains good impact toughness down to -50°C, making it suitable for Arctic and deepwater subsea applications.

5. Good Weldability: Maintains balanced ferrite/austenite ratio in the weld zone when using proper welding procedures, filler metals (e.g., 2509), and heat input control.

6. High Resistance to Erosion and Corrosion Fatigue: Ideal for high-velocity seawater and slurry applications where combined mechanical and corrosive attack occurs.

7. International Certification: Pipes can be certified by ABS, BV, DNV, LR, GL, RINA, CCS, KR, and NK, and comply with NORSOK M-630, ISO 17781, and API 5LC standards for offshore and subsea oil & gas applications.

Womic Steel’s S32750 super duplex pipes conform to multiple international specifications for extreme corrosive and high-pressure service:

These standards ensure that S32750 super duplex pipes meet global requirements for chemical composition, balanced dual-phase microstructure, superior mechanical properties, rigorous testing, and dimensional accuracy.

Note: S32750 contains higher chromium, molybdenum, and nitrogen compared to S32205 (2205), resulting in a PRE value of ≥42 (compared to ≤38 for 316L and ≤35 for 2205). The high nitrogen content promotes austenite stability, significantly increases pitting resistance, and enhances mechanical strength.

Pitting Resistance Equivalent (PRE) Calculation:
PRE = %Cr + 3.3 × %Mo + 16 × %N ≥ 42 (typical 42–45)

Impact Toughness (Charpy V-Notch, typical at -46°C):

Longitudinal: ≥ 70 J (typical)

Transverse: ≥ 50 J (typical)

Heat Treatment Condition:
S32750 super duplex pipes are solution annealed at 1050–1120°C followed by rapid cooling (water quenching) . This heat treatment is critical and must be strictly controlled:

Dissolves unwanted intermetallic phases (sigma, chi, and R-phase) that form rapidly in super duplex grades.

Restores the balanced 40–60% ferrite / 40–60% austenite microstructure.

Relieves internal stresses from forming, rolling, or welding.

Ensures optimal mechanical properties and maximum corrosion resistance.

Critical Note: Unlike standard duplex (2205) or austenitic grades, S32750 super duplex must be water quenched after solution annealing. Air cooling is insufficient and will result in precipitation of brittle intermetallic phases, severely reducing corrosion resistance and toughness.

Delivery Condition: Pipes are normally supplied in solution annealed and pickled condition. Bright annealing is not recommended for super duplex grades due to the need for rapid cooling.

Womic Steel adopts advanced production technology and stringent process control to ensure each S32750 super duplex seamless pipe meets exact specifications with balanced microstructure and flawless surface quality.

1. Raw Material Selection: High-quality S32750 super duplex billets from certified mills (Outokumpu, Sandvik, POSCO, Baosteel) with certified chemical composition and ferrite/austenite balance. Raw material traceability is maintained from melt to final product.

2. Heating and Piercing: Billets heated to a carefully controlled temperature range (lower than austenitic grades to prevent ferrite coarsening and intermetallic formation) and pierced using a rotary piercing mill.

3. Hot Rolling: Shells elongated and rolled to desired intermediate size with strict temperature control.

4. Cold Drawing / Cold Pilgering: Pipes refined to precise dimensions with improved surface finish, enhanced mechanical properties, and work hardening control.

5. Solution Annealing (Intermediate and Final) : Multiple solution annealing steps at 1050–1120°C followed by water quenching to maintain phase balance throughout the manufacturing process.

6. Pickling & Passivation: Removal of oxides using specialized pickling acids optimized for super duplex grades; thorough rinsing to prevent hydrogen pickup.

7. Straightening and Dimensional Calibration: Ensures consistent roundness and wall uniformity without introducing excessive residual stress.

8. Final Inspection & Marking: Each pipe undergoes ferrite content measurement, 100% NDT, dimensional check, and is marked with grade, heat number, standard, and traceability code before packing.

This rigorous process guarantees a balanced dual-phase microstructure, smooth internal bore, high structural integrity, and exceptional corrosion resistance across all batches of Womic Steel’s S32750 Super Duplex Seamless Pipe.

Womic Steel utilizes state-of-the-art manufacturing technology with special procedures for super duplex to ensure every welded pipe meets precise specifications with weld zone phase balance and excellent corrosion resistance.

1. Raw Material Selection: High-quality S32750 super duplex stainless steel strips/coils from certified mills with full traceability.

2. Slitting & Uncoiling: Precision slitting to required width; edge preparation to ensure clean, burr-free edges for welding.

3. Forming & Welding: The strip is progressively formed into a cylindrical shape. The edges are welded using advanced TIG or Plasma welding with:

Strict heat input control (typically 0.5–1.5 kJ/mm)

Shielding gas: Ar + N₂ (2–5% nitrogen) to prevent nitrogen loss and maintain phase balance

Matching or overmatching filler metal (e.g., 2509 / ER2594)

4. Weld Seam Treatment: External weld bead removal and optional internal bead control; weld zone may require light grinding to remove surface oxides.

5. Solution Annealing: Full heat treatment of the entire welded pipe at 1050–1120°C followed by water quenching – absolutely essential for restoring corrosion resistance and balanced microstructure in the weld and HAZ (heat-affected zone).

6. Sizing & Calibration: Final precise outer diameter and roundness.

7. Pickling & Passivation: Chemical treatment removes scale and promotes passive layer formation; extended pickling time may be required for super duplex grades.

8. Non-Destructive Testing (NDT) : Weld seam inspected using:

Eddy Current Testing (ECT)

Ultrasonic Testing (UT) – longitudinal and transverse

Optional: Radiographic Testing (RT) for critical applications

9. Ferrite Content Measurement: Verification of base metal, weld metal, and HAZ phase balance – typically 35–65% ferrite (weld zone may be slightly lower, 30–60%, and is acceptable).

10. Corrosion Testing (mandatory for many specifications): Pitting resistance test per ASTM G48 Method A (ferric chloride) – no pitting at 40°C for 24 hours.

11. Final Inspection & Marking: Complete dimensional check, visual inspection, and traceable marking.

This controlled process guarantees a sound weld seam, excellent dimensional accuracy, balanced super duplex microstructure, and superior corrosion resistance for every batch of Womic Steel’s S32750 Welded Pipe.

Outside Diameter: 6mm – 914mm (1/4″ – 36″) – larger diameters available upon request

Wall Thickness: 0.5mm – 40mm (SCH 10S – SCH XXS)

Length: Up to 12m (fixed or random); longer lengths up to 18m available for seamless

Tolerances: According to ASTM A999 / EN ISO 1127, with additional super duplex-specific requirements for straightness (tighter than austenitic)

*(Refer to ANSI B36.19 / B36.10 dimension tables for detailed schedule matching)*

Womic Steel offers a range of surface finishes for super duplex pipes, each suited to specific industrial and offshore applications.

Note: Bright annealing is generally not recommended for S32750 due to the rapid cooling (water quenching) requirement. All super duplex pipes from Womic Steel are supplied in the annealed and pickled condition unless otherwise specified.

Each S32750 pipe surface is inspected for uniform appearance, absence of pits, surface defects, and consistent finish quality.

Every S32750 super duplex stainless steel pipe undergoes comprehensive inspection in accordance with ASTM, EN, NORSOK, and ISO standards, including super duplex-specific critical tests, to guarantee reliability and performance:

These extensive tests ensure that every S32750 Super Duplex Stainless Steel Pipe from Womic Steel meets the highest international standards for reliability, corrosion resistance, and longevity in the most demanding environments.

S32750 super duplex stainless steel pipe is specified for the most demanding applications where standard duplex (2205) or austenitic grades are insufficient. Womic Steel supplies to global projects with certifications available from all major classification societies.

Each S32750 super duplex stainless steel pipe is packed with extreme care due to the high value and critical nature of these products. Clear labeling includes grade, heat number, dimensions, and project-specific markings.

General packaging for local truck transport:
Bundle packing with woven fabric, iron strip bundle, plastic cap on both ends.

Hexagonal packaging:
Bundle packing with woven fabric, iron strip bundle, plastic cap on two ends.

Packaging for welded pipe in medium and large sizes:
Wrapped with woven fabric by automatic packaging for export sea-worthy transport.

Packaging for medium and large size welded pipes for export:
Wooden or steel crate packaging for export sea-worthy transport – recommended for super duplex to prevent surface damage.

General packaging for products to be exported:
Wooden box for export sea-worthy transport – standard for S32750 seamless pipes.

Packaging for precision tubes and heat exchanger tubes:
Individual wrapping plus wooden box for both local truck and export sea-worthy transport.

Anti-rust protection:
VCI paper interleaving or edge protectors added for high-value super duplex shipments.

1. Direct cooperation with global shipowners ensures the most competitive freight rates for heavy and high-value super duplex shipments.

2. Professional loading and securing teams – super duplex pipes are handled with dedicated care to prevent surface scratches and deformation.

3. Efficient document preparation – includes EN 10204 3.1/3.2 certificates, NORSOK M-630 documentation, material test reports (MTR), and traceability records. Minimizes customs delays.

4. Rapid delivery time – select sizes of S32750 maintained in ready stock; custom sizes available with competitive lead times.

5. Continuous cargo tracking and after-sales follow-up – including pre-shipment inspection coordination and arrival notification.

Womic Steel is a trusted manufacturer and exporter specializing in super duplex stainless steel pipes, committed to delivering premium quality, technical expertise, and professional service for the world’s most demanding projects.

Strict quality control under ISO 9001, PED 2014/68/EU, and NORSOK M-630 compliance.

Super duplex expertise – specialized knowledge in phase balance control, heat treatment (water quenching), and super duplex welding procedures.

Modern production lines – cold pilger mills, automatic TIG welding lines with nitrogen shielding, and in-line solution annealing furnaces with water quenching.

Complete in-house testing – including ferrite measurement, ASTM G48 pitting corrosion testing, and Charpy impact testing at -46°C.

Third-party inspection support – full coordination with SGS, BV, DNV, TUV, LR, and other approved agencies.

Full documentation – EN 10204 Type 3.1/3.2 certificates, material test reports (MTR), NORSOK compliance statements, and complete traceability from melt to final pipe.

Flexible customization – special diameters, wall thicknesses, lengths, beveled ends, and surface finishes.

Fast production cycle – efficient manufacturing for both seamless and welded super duplex pipes.

Reliable global shipping to all major energy hubs (Houston, Aberdeen, Dubai, Singapore, Perth, Rio de Janeiro, Luanda, etc.).

Direct mill pricing – no middlemen, ensuring competitive costs for premium super duplex products.

For inquiries, technical support, or to request a quotation for your specific clad pipe requirements, please contact us:

Website: www.womicstainless.com

E‑mail: info@womicstainless.com

Tel / WhatsApp / WeChat:

Victor: +86 15575100681

Jack: +86 18390957568

Womic Steel – Your reliable partner for high‑quality stainless steel seamless pipes, metallurgically bonded clad tubes, and custom solutions for corrosion‑resistant applications.