ASTM B423
ASTM B423 Alloy Seamless Pipe
ASTM B423 is the standard specification for Nickel-Iron-Chromium-Molybdenum-Copper (Ni-Fe-Cr-Mo-Cu) Alloy Seamless Pipes and Tubes, designed specifically for corrosion-resistant and high-temperature applications. These alloys, led by UNS N08825 (Incoloy 825) and related grades, offer outstanding resistance to strong acids, seawater, stress corrosion cracking, pitting, crevice corrosion, and oxidizing environments.
They are widely used in chemical processing, petrochemical plants, power generation, pollution control, marine applications, and oil & gas industries.
Key Features
Superior corrosion resistance in sulfuric acid, phosphoric acid, and seawater.
High strength at elevated temperatures and thermal stability.
Excellent resistance to pitting, crevice corrosion & SCC (Stress Corrosion Cracking).
Good weldability & fabricability, suitable for aggressive chemical environments.
Long service life in harsh industrial operations.
Technical Specifications
| Property | Description |
|---|---|
| Standard | ASTM B423 |
| Product Form | Seamless Pipes & Tubes |
| Manufacturing Process | Hot or cold finished |
| Applicable Grades | UNS N08825, UNS N08221, UNS N06845, UNS N08825, UNS N08221 |
| Heat Treatment | Solution annealed condition |
| Size Range | Pipe: 6 mm – 355 mm OD (as per order)Tube: 3.35 mm – 101 mm OD |
| Wall Thickness | 0.5 mm – 30+ mm (as required) |
| Surface Finish | Annealed, pickled, bright annealed, cold-drawn |
| Standards Covered | ASTM B423 / ASME SB423 |
ASTM B423 UNS N08825 Chemical Composition (%)
| Element | Percentage (%) |
|---|---|
| Nickel (Ni) | 38.0 – 46.0 |
| Chromium (Cr) | 19.5 – 23.5 |
| Iron (Fe) | Balance |
| Molybdenum (Mo) | 2.5 – 3.5 |
| Copper (Cu) | 1.5 – 3.0 |
| Titanium (Ti) | 0.6 – 1.2 |
| Manganese (Mn) | ≤ 1.0 |
| Silicon (Si) | ≤ 0.5 |
| Carbon (C) | ≤ 0.05 |
| Sulfur (S) | ≤ 0.03 |
| Aluminum (Al) | ≤ 0.2 |
ASTM B423 UNS N08825 Mechanical Properties
| Property | Typical Value |
|---|---|
| Tensile Strength | 586 MPa (≥ 550 MPa minimum) |
| Yield Strength (0.2% Offset) | 240 MPa (≥ 220 MPa minimum) |
| Elongation | ≥ 30% |
| Hardness | ≤ 90 HRB |
ASTM B423 UNS N08825 Physical Properties
| Property | Value |
|---|---|
| Density | 8.14 g/cm³ |
| Melting Point | 1370 – 1400°C |
| Thermal Conductivity | 11.0 W/m·K (at 20°C) |
| Electrical Resistivity | 1.30 µΩ·m (at 20°C) |
| Modulus of Elasticity | 195 GPa |
| Coefficient of Thermal Expansion (20–100°C) | 14.3 µm/m·°C |
| Specific Heat Capacity | 0.46 J/g·K |
Common Grades
- UNS N08825 (commonly known as Incoloy 825)
- UNS N08221
- UNS N06845
Available Sizes
Outside Diameter: 6 mm – 450 mm
Wall Thickness: 0.5 mm – 50 mm
Lengths: Single Random, Double Random, Custom Cut Length
Types of ASTM B423 Pipes
Seamless Pipes
Seamless Tubes
Heat Exchanger Tubes
Boiler & Condenser Tubes
Instrumentation Tubes
U-Bend Tubes
High-Pressure Tubing
Customized Cut Length Tubes
Applications
Petrochemical refineries
Furnace equipment & burners
Superheater & reheater piping
Heat exchangers & boilers
Steam reforming systems
Gas processing & refining
Nuclear power plants
Chemical processing & marine systems