Engineered for severe thermal environments, the ASTM B163 UNS N08810 seamless tube is a nickel-iron-chromium alloy specifically designed for condenser and heat-exchanger service. While standard austenitic alloys degrade under prolonged high-temperature exposure, this product is annealed to develop a controlled grain size (ASTM No. 5 or coarser). This specific metallurgical structure provides optimal resistance to creep and rupture at service temperatures above 1100°F (593°C). It solves the critical problem of tube deformation and premature failure in high-temperature reforming and cracking units.
Manufactured to the strict dimensional limits of ASTM B163 (OD up to 3 in. / 76.2 mm; average wall up to 0.165 in. / 4.19 mm), the N08810 grade offers verified mechanical stability.
| Parameter | Standard Requirement (ASTM B163, Annealed) |
|---|---|
| Tensile Strength, min | 65 ksi (448 MPa) |
| Yield Strength (0.2% offset), min | 25 ksi (172 MPa) |
| Elongation in 2 in. or 50 mm, min | 30% |
| Grain Size | ASTM No. 5 or coarser |
| Typical Chemistry | Ni 30.0–39.0%, Cr 19.0–23.0%, C 0.05–0.10% |
| Grade | Recommended Service Temp. | Primary Advantage |
|---|---|---|
| N08800 | Up to 1100°F (593°C) | Standard oxidation resistance |
| N08810 | Above 1100°F (593°C) | High creep and rupture resistance |
In high-temperature heat exchangers and steam reformer systems, tubes are constantly subjected to thermal cycling and internal pressure. The ASTM B163 N08810 tube ensures structural integrity where standard alloys would yield. Every tube undergoes rigorous testing. According to section 6.5, each tube is subjected to either a hydrostatic test (minimum 1000 psi / 6.9 MPa) or a nondestructive electric test to guarantee zero leakage.
Compliance is strictly maintained within the ASTM B163 framework. The chemical composition conforms to Table 1 limits, and product analysis adheres to Specification B880. Tensile testing is executed via Test Methods E8/E8M, and grain size is verified using E112. Certification reports with actual test results are provided with every shipment.
Q: Why does N08810 require specific grain size control?
A: The controlled grain size (ASTM 5 or coarser) is not just a microstructural feature; it is essential for resisting creep and rupture at temperatures exceeding 1100°F (593°C).
Q: How do you differentiate N08810 from N08800 in procurement?
A: N08810 is the high-carbon variant specifically annealed for high-temperature creep resistance, while N08800 is normally employed for service temperatures up to 1100°F (593°C).
Q: What testing is mandatory for pressure integrity?
A: Each tube is tested via hydrostatic or nondestructive electric methods. For hydrostatic tests, the allowable fiber stress is calculated based on the specific minimum wall thickness to ensure no leakage.
Tubes are supplied with plain ends, cut and deburred. Each bundle or shipping container is marked with the material name, condition (temper), specification number, size, and gross/net weights. Standard export packaging ensures protection against mechanical damage during transit.
To optimize your heat exchanger design and secure your production schedule, contact our engineering team. Please provide your required OD and average/minimum wall thickness.
