Product Code : NI-NI22-CU-CU
Alloy 800HT,Incoloy 800HT,N08811is available in Bar (Round bar, Flat bar), Ribbon, Wire, Rods, Tube, Pipe, Foil, Plate, Sheet, Strip and Forging Stock.
### **Technical Datasheet: Alloy 800HT (Incoloy 800HT, UNS N08811)**
**Overview
** Incoloy 800HT (Alloy 800HT, UNS N08811) is an advanced high-temperature alloy developed from the Alloy 800 series with enhanced creep rupture strength and structural stability. This nickel-iron-chromium alloy features precisely controlled aluminum and titanium contents along with a solution annealing treatment, delivering superior performance in extreme temperature environments up to 1100°C.
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### **Technical Datasheet: Alloy 800HT (Incoloy 800HT, UNS N08811)**
**Overview
** Incoloy 800HT (Alloy 800HT, UNS N08811) is an advanced high-temperature alloy developed from the Alloy 800 series with enhanced creep rupture strength and structural stability. This nickel-iron-chromium alloy features precisely controlled aluminum and titanium contents along with a solution annealing treatment, delivering superior performance in extreme temperature environments up to 1100°C.
### **Technical Datasheet: Alloy 800HT (Incoloy 800HT, UNS N08811)**
**Overview
** Incoloy 800HT (Alloy 800HT, UNS N08811) is an advanced high-temperature alloy developed from the Alloy 800 series with enhanced creep rupture strength and structural stability. This nickel-iron-chromium alloy features precisely controlled aluminum and titanium contents along with a solution annealing treatment, delivering superior performance in extreme temperature environments up to 1100°C.
**Key Characteristics**
- **Enhanced creep and rupture strength** at temperatures above 600°C
- **Excellent resistance to oxidation and carburization**
- **Superior microstructural stability**
under long-term exposure to high temperatures
- **Good resistance to sulfidation and reducing atmospheres**
- **Optimized high-temperature mechanical properties
** through controlled chemistry and processing
--- #### **1. Chemical Composition (Weight %)**
| Element | Composition (%) |
|---------|-----------------|
| **Nickel (Ni)** | 30.0-35.0 |
| **Chromium (Cr)** | 19.0-23.0 |
| **Iron (Fe)** | Balance |
| **Carbon (C)** | 0.06-0.10 |
| **Aluminum (Al)** | 0.25-0.60 |
| **Titanium (Ti)** | 0.25-0.60 |
| **Manganese (Mn)** | ≤1.50 |
| **Silicon (Si)** | ≤1.00 |
| **Copper (Cu)** | ≤0.75 |
| **Sulfur (S)** | ≤0.015 |
***Critical Ratio:** Al + Ti ≥ 0.85% (This specific requirement distinguishes 800HT from other 800 series alloys)*
2. Physical Properties
| Property | Value |
|----------|-------|
| **Density** | 7.94 g/cm³ |
| **Melting Range** | 1350-1400°C |
| **Thermal Conductivity** | 11.5 W/m·K |
| **Specific Heat** | 500 J/kg·K |
| **Coefficient of Thermal Expansion** | 14.4 μm/m·°C |
| **Modulus of Elasticity** | 195 GPa |
--- #### **3. Mechanical Properties**
**Room Temperature (Solution Annealed):**
- **Tensile Strength**: 450-690 MPa
- **Yield Strength (0.2% Offset)**: 170-345 MPa
- **Elongation**: 30-45%
**High Temperature Performance:**
- **Maximum service temperature**: 1100°C
- **Excellent creep rupture strength** at 650-950°C
- **Superior stress rupture properties** compared to 800H
--- #### **4. International Standards**
| Product Form | Standard |
|--------------|----------|
| **Plate, Sheet, Strip** | ASTM B409, ASME SB409 |
| **Bar & Forgings** | ASTM B408, ASME SB408 |
| **Seamless Tubing** | ASTM B163, B407 |
| **Pipe & Tubes** | ASTM B564, B517 |
| **European Standard** | EN 10095 |
| **Unified Numbering** | UNS N08811 |
| **ASME Code Case** | 1980 |
--- #### **5. Applications**
**Petrochemical Processing:**
- Steam methane reformer tubes and headers
- Ethylene cracking furnace tubes
- Pyrolysis coils and transfer lines
- Heater tubes in direct-fired service
**Thermal Processing:**
- Radiant tubes and charge baskets
- Annealing furnace components
- Carburizing fixtures and retorts
- Heat treatment furnace rolls
**Power Generation:**
- Superheater and reheater tubes
- Heat recovery steam generators
- Gas turbine combustion components
- High-temperature heat exchangers
**Nuclear Industry:**
- Intermediate heat exchangers
- Steam generator components
- High-temperature gas-cooled reactor systems
--- **Summary**
Incoloy 800HT (UNS N08811) represents the premium grade in the Alloy 800 series, specifically engineered for the most demanding high-temperature applications. The controlled chemistry requirements, particularly the Al + Ti ≥ 0.85% ratio, combined with solution annealing treatment, provide enhanced creep rupture strength and microstructural stability superior to both Alloy 800 and 800H. This makes 800HT the material of choice for critical components in petrochemical reforming, ethylene production, and high-temperature heat treatment equipment where long-term reliability at extreme temperatures is essential. The alloy is fully recognized in international standards and approved for use in ASME Boiler and Pressure Vessel Code applications.
Packing of Incoloy 800HT (UNS N08811)
Standard Packing:
Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 1645 gallon liquid totes Special package is available on request.
