Excerpt:
Incoloy 800 (UNS N08800) supplier — ASTM B408/B407/B409. Nickel-iron-chromium alloy for heat exchangers, furnace components up to 760°C. Resistant to oxidation and carburization.
Shanghai Hangbo Alloy Group Co., Ltd. provides premium quality Incoloy 800 (UNS N08800) and Incoloy 800H (UNS N08810) for high-temperature structural applications. These alloys are known for their stable performance and oxidation resistance in thermal processing environments.
Overview
Incoloy 800 (UNS N08800) is a nickel-iron-chromium alloy combining high-temperature strength with excellent resistance to oxidation, carburization and nitriding, together with good corrosion resistance in aqueous media. With nickel 30–35%, chromium 19–23% and iron 39.5% min, the alloy bridges the gap between austenitic stainless steels and higher-cost nickel alloys, and is a long-established material for process equipment operating up to 593°C in continuous service. Shanghai Hangbo Alloy Group supplies Incoloy 800 as round bar (ASTM B408), plate, sheet and strip (ASTM B409) and seamless pipe and tube (ASTM B407), each heat certified with full mill test documentation.
ASTM Standards & Specifications
- ASTM B407: Standard Specification for Nickel-Iron-Chromium Alloy Seamless Pipe and Tube.
- ASTM B409: Standard Specification for Nickel-Iron-Chromium Alloy Plate, Sheet, and Strip.
Chemical Composition (ASTM B407/B409)
| Element | Ni | Fe | Cr | C (800) | C (800H) | Al + Ti (800H) |
|---|---|---|---|---|---|---|
| Min (%) | 30.0 | 39.5 | 19.0 | - | 0.05 | 0.85 |
| Max (%) | 35.0 | - | 23.0 | 0.10 | 0.10 | 1.20 |
Mechanical Properties (at 800°C)
Incoloy 800H is specifically controlled for carbon and grain size to maximize creep-rupture strength at temperatures above 600°C. At 800°C (1472°F), the alloy maintains high structural stability and resistance to carburization.
Mechanical Properties (Annealed, ASTM B408/B409)
Room-temperature mechanical properties (minimum values) of annealed Incoloy 800 (UNS N08800) per ASTM B408 (round bar) and ASTM B409 (plate, sheet, strip):
| Property | Minimum Value |
|---|---|
| Tensile Strength | 520 MPa (75 ksi) |
| Yield Strength (0.2% offset) | 205 MPa (30 ksi) |
| Elongation (in 2 in. / 50 mm) | 30% |
Material Characteristics & Applications
Incoloy 800 series alloys offer high strength and resistance to oxidation and carburization at high temperatures. Incoloy 800H is preferred for high-stress applications due to its higher carbon content and solution annealing treatment.
- Oxidation Resistance: Resists scaling and internal oxidation at temperatures up to 800°C+.
- Creep Strength: Superior long-term strength in the 600°C-800°C range.
- Applications: Ethylene cracking furnace components, pigtails, headers, and steam generator tubing in nuclear power plants.
Global Project Case: Ethylene Cracking Furnace
Scenario: A petrochemical plant required durable pigtail tubes for an ethylene cracking furnace operating continuously at 800°C. The material needed to resist carburization and maintain creep strength over long cycles.
Solution: Hangbo Alloy supplied Incoloy 800H pigtail tubes and manifold components. The precise control of Al+Ti content ensured optimal creep performance.
Service Performance: The furnace has maintained stable operation at 800°C for over 5 years. Routine inspections showed minimal carburization and no creep-induced deformation, validating the alloy's high-temperature durability.
Pros, Cons & FAQ
Pros
- Excellent high-temperature creep strength (800H).
- High resistance to carburization and nitriding.
- Economical choice for high-temperature service compared to pure nickel alloys.
Cons
- Less resistant to corrosion in aqueous environments compared to Incoloy 825.
- Subject to sigma phase embrittlement if exposed to specific temperature ranges for extended periods.
FAQ
Q: What is the maximum service temperature for Incoloy 800/800H?
A: Incoloy 800 is generally used for service up to 593°C (1100°F). For higher temperatures, Incoloy 800H and 800HT are preferred, as they are specifically processed to maintain high creep-rupture properties up to 815°C (1500°F) or even higher in low-stress applications.
Q: How does Incoloy 800 resist carburization?
A: The high nickel and chromium content in Incoloy 800 provides excellent resistance to carburization and nitriding. This makes it a primary choice for heat-treating fixtures and petrochemical furnace components where exposure to carbon-rich gases is common.
Q: Can Incoloy 800 be used in nuclear power plants?
A: Yes, Incoloy 800 is widely used for steam generator tubing in pressurized water reactors (PWR) and high-temperature gas-cooled reactors (HTGR). Its resistance to stress-corrosion cracking and high-temperature stability are critical in these safety-critical environments.
Q: Is Incoloy 800 weldable to other stainless steels?
A: Yes, Incoloy 800 can be readily welded to other stainless steels or nickel alloys using standard welding methods. Typically, nickel-based filler metals like Inconel 82 or Inconel 182 are used to ensure the weld joint maintains similar high-temperature properties and corrosion resistance.
Q: What is the main difference between 800 and 800H?
A: 800H has a higher carbon content (0.05-0.10%) and is solution annealed to ensure superior creep and rupture strength at temperatures above 600°C.
Internal Links to Related Alloys
- Incoloy 825 - For enhanced aqueous corrosion resistance.
- Inconel 625 - For higher strength and extreme fatigue resistance.
- Nimonic 80A - For high-temperature fastening applications.
