Stainless pipe fitting,stainless fitting,duplex stainless,31803,32750,32760,we are one of largest sour service stainless fitting supplier according to ISO 10156.
C&N supplies high-quality ASTM A182 F51 Weld Neck Raised Face (WN RF) Flanges and Blind Flanges, forged from duplex stainless steel (UNS S31803 / 2205) for outstanding corrosion resistance and mechanical strength in severe environments. These flanges are fully compliant with NACE MR0175 / ISO 15156 for sour service applications, with controlled hardness, microstructure, and thorough testing including PMI and chemical analysis.
The duplex microstructure provides an excellent combination of high tensile strength and superior resistance to pitting, crevice corrosion, and chloride stress corrosion cracking. The weld neck design with raised face ensures proper alignment, stress distribution, and reliable sealing in high-pressure systems.
ASTM A182 F51 Chemical Composition (%)
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.030 |
| Manganese (Mn) | ≤ 2.00 |
| Phosphorus (P) | ≤ 0.030 |
| Sulfur (S) | ≤ 0.020 |
| Silicon (Si) | ≤ 1.00 |
| Chromium (Cr) | 21.0 – 23.0 |
| Nickel (Ni) | 4.5 – 6.5 |
| Molybdenum (Mo) | 2.5 – 3.5 |
| Nitrogen (N) | 0.08 – 0.20 |
Note: Composition meets ASTM A182 requirements for Grade F51 (UNS S31803). For NACE MR0175/ISO 15156 sour service, additional controls on ferrite content (typically 35-65%) and impurities apply.
ASTM A182 F51 Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength (min) | 620 MPa (90 ksi) |
| Yield Strength (min) | 450 MPa (65 ksi) |
| Elongation (min) | 25% |
| Hardness (typical for NACE) | ≤ 28 HRC / 290 HB |
These properties are achieved through solution annealing and rapid cooling, delivering twice the strength of standard austenitic grades while maintaining good ductility.
Dimensions and Standards
- Specifications → ASTM A182 / ASME SA182
- Dimensions → ASME B16.5 (NPS 1/2″ to 24″), larger sizes per ASME B16.47 or custom
- Pressure Ratings → Class 150, 300, 600, 900, 1500, 2500
- Facing → Raised Face (RF), standard serrated finish
- Types → Weld Neck (WN), Blind (BL), with matching bore schedules (e.g., SCH80S)
- Heat Treatment → Solution annealed and water quenched
- Testing & Certification → PMI, chemical analysis, ultrasonic, hydrostatic (as required), full traceability with heat number marking
Key Features
- Exceptional resistance to chloride environments and sour service (H2S)
- High PREN value (>34) for superior pitting and crevice corrosion resistance
- Weld neck hub reduces stress concentration and turbulence
- Duplex structure combines ferritic strength with austenitic corrosion performance
- NACE MR0175 / ISO 15156 compliant for oil & gas sour applications
- Full material testing including on-site PMI verification
Applications
- Offshore platforms and subsea pipelines
- Oil and gas production in sour (H2S-containing) environments
- Chemical and petrochemical processing
- Desalination and seawater handling systems
- Pulp and paper industry
- Heat exchangers and pressure vessels
As a reliable manufacturer and stockist of duplex stainless steel flanges, C&N ensures rigorous quality control at every stage—from raw material verification and forging to machining, heat treatment, PMI inspection, and detailed marking. We provide complete mill certificates, third-party inspections when needed, and protective packaging for safe global delivery.
Contact us for quotations or technical details on ASTM A182 F51 WN RF Flanges or Blind Flanges. Our team can assist with material selection, custom dimensions, and fast turnaround to meet your project requirements.
