What Is a Seamless Incoloy 825 Pipe?
Seamless Incoloy 825 Pipe is a high-performance, corrosion-resistant pipe crafted from a single, solid billet of a nickel-iron-chromium-molybdenum-copper alloy. It’s manufactured without a weld joint, ensuring superior structural integrity and reliability, especially under high-stress and highly corrosive conditions. The “Incoloy 825” designation refers to a specific grade known for its exceptional resistance to a wide range of corrosive environments. Its unique composition, which includes copper and molybdenum, provides outstanding resistance to both oxidizing and reducing acids, as well as to pitting and crevice corrosion. This makes it a top choice for demanding applications in the chemical processing, oil and gas, and pollution control industries.
Size Range: OD 6–457 mm · WT 0.5–45 mm
Key Features and Advantages
Seamless Incoloy 825 Pipes offer a unique combination of benefits that make them invaluable in the most demanding industries:
Exceptional Corrosion Resistance: Provides outstanding resistance to a wide range of corrosive media, including sulfuric, phosphoric, and nitric acids. The high molybdenum and copper content also offers excellent resistance to chloride-ion stress-corrosion cracking, pitting, and crevice corrosion.
High Pressure and Temperature Tolerance: The seamless construction and robust material allow the pipe to safely handle high internal pressures and a wide range of operating temperatures.
Good Mechanical Properties: It maintains high tensile and yield strength, providing reliable performance in high-stress applications.
Superior Weldability: The alloy can be welded using standard methods without the risk of post-weld corrosion, thanks to its stabilized composition.
Versatility: Its broad resistance to various corrosive chemicals makes it a highly versatile material for a wide range of applications.
Product Specifications and Data
To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for Incoloy 825.
Equivalent Grade
| UNS | Common grade name | EN material number | EN steel name | JIS grade | GB/T grade |
|---|---|---|---|---|---|
| N08825 | Incoloy 825 | 2.4858 | NiCr21Mo | NCF825 | NS1402 / NS142 (legacy) |
Grade correspondence does not make ASTM, ASME, EN, JIS and GB delivery requirements interchangeable. Confirm chemistry, heat treatment, mechanical properties, dimensions, testing and certification against the purchase specification. See the grade designation index.
Chemical Composition
The composition of Incoloy 825 is carefully balanced to achieve its superior corrosion resistance and high strength.
| Ni | Cr | Fe | Mn | C | Cu | Si | S | Al | Mo | Ti |
|---|---|---|---|---|---|---|---|---|---|---|
| 38.00-46.00 | 19.50-23.50 | ≥22.00 | ≤1.00 | ≤0.05 | 1.50-3.00 | ≤0.50 | ≤0.03 | ≤0.20 | 2.5-3.5 | 0.6-1.2 |
Typical Mechanical Properties
Incoloy 825 is specifically designed to maintain its strength and shape in high-stress, corrosive environments.
| Tensile Strength | Yield Strength | Elongation | Hardness |
|---|---|---|---|
| ≥ 586 MPa | ≥ 241MPa | ≥ 30% | ≤ 192 HBW |
Per ASTM B423 Table A1.1 — Cold-worked Annealed.
Typical Physical Properties
These physical properties highlight the material’s ability to perform reliably under a wide range of conditions.
| Density | Melting Point | Thermal Expansion | Thermal Conductivity | Modulus of Elasticity | Electrical Resistivity |
|---|---|---|---|---|---|
| 8.14 g/cm³ | 1340 – 1400 °C approx. | 14.0 μm/m·°C (20-100°C) | 11.1 W/m·K (20°C) | 195 GPa | 1.14 × 10⁻⁶ Ω·m (20°C) |
Size Tolerance Chart (mm)
Cold-Finished Pipes and Tubes:
| Specified/Calculated Nominal OD (Inches) | Permissible Variation (Inches) | Specified/Calculated Nominal OD (mm) | Permissible Variation (mm) |
| 0.500 to 5⁄8, excl. | ±0.005 | 12.7 to 15.8, excl. | ±0.127 |
| 5⁄8 to 1 1⁄2, incl. | ±0.0075 | 15.8 to 38.1, incl. | ±0.190 |
| Over 1 1⁄2 to 3 1⁄2, incl. | ±0.010 | Over 38.1 to 88.9, incl. | ±0.254 |
| Over 3 1⁄2 to 4 1⁄2, incl. | ±0.015 | Over 88.9 to 114.3, incl. | ±0.381 |
| Over 4 1⁄2 to 6, incl. | ±0.020 | Over 114.3 to 152.4, incl. | ±0.508 |
| Over 6 to 6 5⁄8, incl. | ±0.025 | Over 152.4 to 168.3, incl. | ±0.635 |
| Specified/Calculated Nominal OD (Inches) | Permissible Variation (Inches) | Specified/Calculated Nominal OD (mm) | Permissible Variation (mm) |
| 2 1⁄2 to 5 1⁄2, excl. | ±0.031 | 63.5 to 139.7, excl. | ±0.787 |
| 5 1⁄2 to 9 1⁄4, incl. | ±0.047 | 139.7 to 234.9, incl. | ±1.19 |
| Condition | Specified/Calculated Nominal OD (Inches) | Permissible Variation (Wall Thickness) |
| Cold-Finished | 0.500 to 5⁄8, excl. | ±15.0% |
| 5⁄8 to 4 1⁄2, incl. | ±10.0% | |
| Over 4 1⁄2 to 6 5⁄8, incl. | ±12.5% | |
| Hot-Finished | 2 1⁄2 to 9 1⁄4, incl. | ±12.5% |
Common Industrial Applications
The combination of high corrosion resistance and good mechanical properties of seamless Incoloy 825 pipes makes them a preferred choice for:
Chemical Processing
Used in reactors, heat exchangers, and piping for handling sulfuric, phosphoric, and other aggressive acids.
Oil and Gas Industry
For piping, risers, and manifolds in sour gas service and other corrosive environments.
Pollution Control
In scrubbers and stack liners for flue-gas desulfurization (FGD) systems.
Marine Engineering
For seawater applications and components where resistance to saltwater corrosion is critical.
Frequently Asked Questions
What sizes are available for Incoloy 825 seamless pipe?
Continuous supply covers OD 6–457 mm and WT 0.5–45 mm. Requirements outside this range are reviewed against mill capability on request.
Which specification governs Incoloy 825 seamless pipe?
ASTM B423 / ASME SB423 is the governing seamless specification for UNS N08825; the edition in force at order time is stated on the quotation and purchase order.
What inspection documents are provided?
Each order is documented with a mill test certificate stating heat chemistry and mechanical test results. EN 10204 3.1 certification, hydrostatic testing, eddy-current or ultrasonic inspection and PMI are performed when specified in the purchase order.
Technical review: page data reviewed by the Xinzhe technical desk on 2026-09-27. Property values are typical reference data compiled from Special Metals Corporation alloy data sheets and the governing ASTM specifications; they are not acceptance guarantees unless stated in the purchase order. "Incoloy" is a trademark of Special Metals Corporation, used here to identify the alloy family only.
Ready to Request a Quotation?
Send the NPS and schedule (or actual OD and wall), quantity, length, end finish and the inspection items you need as acceptance criteria — you will get a written quotation stating the specification and edition, delivery condition, documents included and lead time.
