Alloy 800HT UNS N08811: Properties, Applications, and Performance Guide
Alloy 800HT UNS N08811 is a nickel-iron-chromium superalloy known for its excellent high-temperature strength and outstanding resistance to oxidation and carburization. This material is widely used in demanding industrial environments where reliability at elevated temperatures is critical.
Mechanical Properties and Heat Resistance
The alloy maintains remarkable mechanical strength and structural stability at temperatures up to 1500°F (815°C). Its controlled carbon content and titanium/aluminum ratio ensure superior creep and stress rupture properties, making it ideal for prolonged high-temperature service.
Chemical Composition and Microstructure
With approximately 30-35% nickel, 19-23% chromium, and balanced iron content, Alloy 800HT UNS N08811 delivers exceptional metallurgical stability. The carefully engineered composition provides optimal performance in both oxidizing and reducing atmospheres.
Industrial Applications and Use Cases
This high-performance alloy serves critical functions across multiple industries. Its unique combination of properties makes it particularly valuable in energy and processing sectors.
Petrochemical and Chemical Processing
In chemical processing equipment, the alloy demonstrates excellent resistance to sulfur attack and chloride stress corrosion cracking. It’s commonly specified for reformer furnace components, heat exchangers, and radiant tubes.
Power Generation Systems
Nuclear and conventional power plants utilize Alloy 800HT UNS N08811 for steam generator tubing, superheater sections, and other high-temperature components requiring long-term reliability under thermal cycling conditions.
Performance Advantages and Technical Specifications
The material’s performance characteristics make it superior to many alternative alloys in specific high-temperature applications. Understanding these advantages helps engineers make informed material selection decisions.
Oxidation and Corrosion Resistance
At elevated temperatures, the alloy forms a protective chromium oxide scale that resists spalling and provides continuous protection against oxidative damage. This property significantly extends component service life.
Thermal Stability and Creep Behavior
Alloy 800HT UNS N08811 maintains dimensional stability and mechanical properties during long-term exposure to high temperatures, demonstrating minimal creep deformation under sustained loads.
Frequently Asked Questions
What distinguishes Alloy 800HT from other nickel alloys?
The material’s optimized titanium/aluminum ratio and controlled carbon content provide enhanced strength at high temperatures compared to standard nickel-chromium alloys.
Can Alloy 800HT UNS N08811 be welded effectively?
Yes, the alloy demonstrates good weldability using matching filler metals and proper procedures, though post-weld heat treatment may be necessary for some applications.
What temperature range is suitable for this material?
The alloy performs optimally in temperatures ranging from 1100°F to 1500°F (593°C to 815°C), making it suitable for most high-temperature industrial processes.
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For engineers and procurement specialists seeking reliable high-temperature solutions, Alloy 800HT UNS N08811 represents an excellent balance of performance and cost-effectiveness. This versatile super