Alloy 926 has a PREN of approximately 46, calculated as %Cr + 3.3×%Mo + 16×%N. A PREN above 40 indicates super-austenitic capability for seawater service at high temperatures, placing UNS N08926 in this class.
ASTM B677 Alloy 926 Seamless Pipe
Alloy 926 seamless pipe is a super-austenitic 6Mo stainless steel pipe identified by UNS N08926 and the European designation W.Nr. 1.4529 / EN X1NiCrMoCuN25-20-7. Also referenced under the trade name Incoloy 25-6MO, this grade belongs to the 6% molybdenum austenitic family, a class defined by PREN values above 40 and near-immunity to chloride pitting. We at Xintongda act as manufacturer, stockist and leading supplier of ASTM B677 Alloy 926 Seamless Pipe.
Its nominal composition of 19–21% Cr, 24–26% Ni, 6–7% Mo, 0.5–1.5% Cu, and 0.15–0.25% N gives it a distinct corrosion performance advantage over standard 316L and 904L grades in aggressive chloride environments. Cold rolling, cold drawing, annealing, pickling, and straightening produce seamless pipes under ASTM B677 and B673. It works in cryogenic and elevated-temperature chloride duty from -196 to 450°C.
We manufacture UNS N08926 seamless pipe with an annual capacity of 25,000 tonnes, available for sale within about one week from stock or 15 to 60 days for manufacturing orders.
Product specifications:
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Standard
ASTM B677
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OD Range
6-457 mm
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Thickness
1-65 mm
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Length
≤ 18 m
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How Alloy 926 Seamless Pipe is Produced
We ensure high-quality alloy 926 seamless pipes by adhering to strict manufacturing procedures. Production begins with a super-austenitic 6Mo stainless steel ingot, which is hot-extruded or pierced to form the seamless hollow. The hollow then undergoes cold drawing, cold rolling, or pilger processing to reach precise dimensional tolerances.
Solution annealing improves grain microstructure and corrosion resistance. Pickling eliminates surface oxides, and then pipes are straightened to tolerances. Hydrostatic and eddy-current tests check integrity before cut-to-length finishing and export packaging. Learn about our production process on our page.
Key Features of Alloy 926 Seamless Pipe
The following are key features of Alloy 926 that ensure the quality of the Alloy 926 Seamless Pipe makes it ideal for major applications.
- Superior chloride pitting resistance: A PREN of approximately 46, calculated as %Cr + 3.3×%Mo + 16×%N, provides exceptional pitting resistance in seawater, produced water, and acid-chloride process streams at elevated temperatures.
- Excellent resistance to chloride SCC: High nickel (24–26%) and molybdenum (6–7%) content delivers near-immunity to chloride stress corrosion cracking in service environments up to 150 °C, well beyond the capability of standard austenitic grades.
- Good resistance to sulfuric and phosphoric acids: Copper and increased molybdenum prevent corrosion in dilute-to-intermediate sulphuric acid and wet-process phosphoric acid under a variety of chemical process conditions.
- High strength and toughness: Nitrogen strengthening yields tensile strength above 650 MPa (94.3 ksi) with retained toughness at cryogenic temperatures, meeting the demands of high-pressure piping design across wide temperature excursions.
- Weldable with matching filler: 1.4529 pipe is weldable by GTAW, GMAW, and SMAW using matching 6Mo filler. Overmatching nickel-base filler is sometimes specified for full corrosion property retention in critical joints.
- Cost-effective vs nickel-base alloys: Provides performance comparable to several nickel-base alloys at reduced cost in chloride-dominated environments, making it the preferred engineering choice for seawater piping, FGD systems, and similar applications
ASTM B677 Alloy 926 Seamless Pipe Equivalent Materials
The table below lists common international equivalents to support a consistent supply for engineering projects worldwide.
| Standard | Designation |
| UNS | N08926 |
| DIN/EN | 1.4529 / X1NiCrMoCuN25-20-7 |
100% Certified Testing & Documentation
Every shipment of Alloy 926 seamless pipe leaves our facility with comprehensive documentation verifying chemistry, mechanical performance, corrosion behaviour, and dimensional accuracy. Xintongda supports third-party-inspected and code-compliant project supply with full traceability from raw material heat to finished pipe
- EN 10204 3.1 and EN 10204 3.2 Material Test Certificates (MTC)
- Raw Materials Certificate
- 100% PMI (Positive Material Identification)
- Heat Treatment Charts
- Third-Party Inspection Report (TPI / TUV / BV / SGS)
- Surface roughness and dimensional measurement
- Manufacturer Test Certificate (Impact, Flattening, Flare, Bend, Hardness, Intergranular, Pitting Corrosion, Grain Size, ET, UT, HT)
- Laboratory Test Certificate from Government-Approved Lab
Alloy 926 Seamless Pipe Industrial Applications
UNS N08926 pipe serves chloride-intensive industries where standard stainless grades fail. Key application sectors include the following:
Offshore Oil and Gas Topsides Piping
Alloy 926, utilised in seawater and firewater systems, inhibits chloride pitting and complies with stringent NORSOK criteria for resilient offshore energy infrastructure.
Seawater-Cooled Heat Exchangers
These pipes resist crevice corrosion in seawater condensers, offering significantly longer service lives than standard duplex or 904L stainless steel alternatives.
Flue Gas Desulfurisation Systems
To ensure material integrity during sulfur dioxide absorption, Alloy 926 withstands acidic, chloride-rich slurries. It is the perfect fit for your scrubber internals.
Pulp and Paper Bleaching Plants
Specifically engineered for chlorine dioxide stages, this grade stabilises performance in oxidising environments where standard austenitic steels typically fail.
Chemical Processing Piping
Reliably handles mixed acids and organic chlorides in pharmaceutical plants, maintaining safety during multi-stage chemical reactions at elevated temperatures.
Desalination Plants
Essential for brine heaters and high-pressure piping, this alloy resists concentrated salt solutions, ensuring long-term dependability in reverse-osmosis facilities.
Frequently Asked Questions
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What is the PREN of Alloy 926, and why is it important?
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How does Alloy 926 differ from 904L stainless steel?Alloy 926 provides a 30% higher pitting resistance index and enhanced tensile properties compared to 904L, attributable to its elevated molybdenum content (6–7% versus 4–5%) and nitrogen levels. IT is favoured when service temperatures or chloride concentrations surpass the capabilities of 904L.
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Is Alloy 926 suitable for NACE sour service?Yes. Alloy 926 meets NACE MR0175 / ISO 15156 sour-service criteria when solution-annealed and hardened below limitations. Mill certifications confirming compliance are available on request.
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What standards apply to Alloy 926 seamless pipes?Seamless pipes are manufactured to ASTM B677 and ASTM B673. ASME SB-677 covers code service applications. Additional corrosion tests to ASTM G48 and ASTM A262 can be performed on request for project-specific qualification.