Comprehensive Guide to Seamless Hastelloy B3 Tubes (UNS N10675) : Properties, Specifications, and Industrial Applications
What is a Seamless Hastelloy B3 Tube?
A Seamless Hastelloy B3 (UNS N10675) tube is a high-performance nickel–molybdenum (Ni–Mo) alloy tube designed for use in highly corrosive and high-temperature environments. Manufactured through hot extrusion and cold pilgering from a solid billet, seamless tubes eliminate weld seams, resulting in:
- Enhanced structural integrity
- Uniform metallurgical grain structure
- Superior resistance to pressure and corrosion
Hastelloy B3 is an advanced evolution of Hastelloy B2, offering improved thermal stability and significantly reduced susceptibility to intermetallic phase precipitation. This advancement minimizes risks such as embrittlement during fabrication and welding.
Size Range: OD 6–457 mm · WT 0.6–35 mm
Key Features and Technical Advantages
1. Exceptional Corrosion Resistance
Hastelloy B3 demonstrates outstanding resistance to reducing chemical environments, including:
- Hydrochloric acid (HCl) — all concentrations and temperatures
- Sulfuric acid
- Phosphoric acid
- Acetic acid
This makes it one of the most reliable materials for aggressive chemical processing systems.
2. Superior Thermal Stability
Unlike earlier B-series alloys, Hastelloy B3 maintains mechanical integrity within the temperature range:538℃ to 815℃
This stability reduces the likelihood of Stress Corrosion Cracking (SCC) and ensures long-term durability under fluctuating thermal conditions.
3. Excellent Weldability and Fabrication Performance
Hastelloy B3 tubes offer improved resistance to:
- Knife-line attack
- Heat-Affected Zone (HAZ) corrosion
They are suitable for standard welding processes such as:
- GTAW (TIG welding)
- GMAW (MIG welding)
4. High Pressure and Mechanical Reliability
The seamless construction eliminates longitudinal weld defects, allowing:
- Higher allowable working pressures
- Compliance with ASME Boiler and Pressure Vessel Code
- Increased safety in critical applications
Chemical Composition of Hastelloy B3 (UNS N10675)
Product Specifications and Data
To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for Hastelloy B3.
Equivalent Grade
| UNS | Common grade name | EN material number | EN steel name | JIS grade | GB/T grade |
|---|---|---|---|---|---|
| N10675 | Hastelloy B-3 | 2.4600 | NiMo29Cr | – | NS3203 |
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 Hastelloy B3 is carefully balanced to achieve its superior corrosion resistance and high thermal stability.
Key Insight:
The high nickel and molybdenum content is responsible for its exceptional resistance to reducing acids.
| Grade | Ni | Cr | Mo | Fe | W | C | Si | Co | Mn | V | P | S | Ti | Cu | Al | Zr |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| N10675 | ≥65.00 | 1.00-3.00 | 27.00-32.00 | 1.00-3.00 | ≤3.00 | ≤0.01 | ≤0.10 | ≤3.00 | ≤3.00 | ≤0.20 | ≤0.03 | ≤0.010 | ≤0.20 | ≤0.20 | ≤0.50 | ≤0.10 |
Typical Mechanical Properties
- The composition of Hastelloy B3 is carefully balanced to achieve its superior corrosion resistance and high thermal stability.
| Tensile Strength | Yield Strength | Elongation | Hardness |
|---|---|---|---|
| ≥ 760 MPa | ≥ 350 MPa | ≥ 40% | Not an acceptance limit in ASTM B622-23 |
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 |
|---|---|---|---|---|---|
| 9.22 g/cm³ | 1370 – 1418 °C | 10.6 μm/m·°C (25-100 °C) | 11.2 W/m·K (20°C) | 216 GPa | 1.37 μΩ·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% |
Industrial Applications of Seamless Hastelloy B3 Tubes
Seamless Hastelloy B3 tubing is widely used in critical industrial environments where corrosion resistance and reliability are essential:
Chemical Processing Industry (CPI)
- Hydrochloric acid production systems
- Alkylation units
- Agrochemical manufacturing (herbicides, pesticides)
Petrochemical Industry
- Heat exchangers
- Reactors exposed to aggressive catalysts
- High-temperature processing systems
Pharmaceutical Industry
- High-purity processing equipment
- Systems exposed to organic acids and halides
Energy and Environmental Applications
- Hydrogen production systems
- Waste-to-energy plants
- Advanced corrosion-resistant piping systems
Seamless Hastelloy B3 (UNS N10675) tubes represent a next-generation corrosion-resistant alloy solution for industries requiring extreme durability, thermal stability, and chemical resistance. With superior performance over traditional B-series alloys, they are an optimal choice for high-risk, high-value industrial systems.
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