Alloy 800HT,Incoloy 800HT Other/Similar Specs,N08811,E FORU

British Specs:BS 3072 BS 3073 BS 3074 BS 3075 BS 3076 NA15，American Specs:AMS 5766 Bar and Forgings AMS 5871 Sheet, Strip and Plate ASTM B408 ASTM B564 ASTM A240 ASTM A480，German Specs:WS 1.4876 WS 1.4958 WS 1.4959

**Technical Datasheet: Alloy 800HT / Incoloy 800HT & Related Specifications (UNS N08811)** --- ### **1.0 Comprehensive Product Overview** **Alloy 800HT** (commercially known as **Incoloy 800HT**, UNS **N08811**) represents the premium grade within the 800 series nickel-iron-chromium superalloys, featuring enhanced high-temperature properties through strict control of carbon, aluminum, and titanium content. This overview covers the complete spectrum of Alloy 800HT specifications, including closely related grades and their specific applications across various international standards. The "HT" designation specifically indicates the high-temperature optimized variant with controlled carbon content (0.06–0.10%) and elevated aluminum+titanium ratios (Al + Ti ≥ 1.20%), providing superior creep rupture strength and microstructural stability compared to both standard Alloy 800 and Alloy 800H. --- ### **2.0 Chemical Composition Comparison** | Element | Alloy 800HT (N08811) | Alloy 800H (N08810) | Alloy 800 (N08800) | |---------|---------------------|-------------------|-------------------| | **Nickel (Ni)** | 30.0–35.0 | 30.0–35.0 | 30.0–35.0 | | **Chromium (Cr)** | 19.0–23.0 | 19.0–23.0 | 19.0–23.0 | | **Iron (Fe)** | ≥39.5 | ≥39.5 | ≥39.5 | | **Carbon (C)** | 0.06–0.10 | 0.05–0.10 | 0.05 max | | **Aluminum (Al)** | 0.25–0.60 | 0.15–0.60 | 0.15–0.60 | | **Titanium (Ti)** | 0.25–0.60 | 0.15–0.60 | 0.15–0.60 | | **Al + Ti** | **≥1.20** | ≥0.85 | - | | **Manganese (Mn)** | ≤1.50 | ≤1.50 | ≤1.50 | | **Silicon (Si)** | ≤1.00 | ≤1.00 | ≤1.00 | --- ### **3.0 Physical Properties Summary** | Property | Alloy 800HT | Alloy 800H | Alloy 800 | |----------|-------------|------------|-----------| | **Density** | 8.03 g/cm³ | 8.03 g/cm³ | 8.03 g/cm³ | | **Melting Range** | 1354–1384°C | 1354–1384°C | 1354–1384°C | | **Thermal Expansion** | 16.6 × 10⁻⁶ /K | 16.6 × 10⁻⁶ /K | 16.6 × 10⁻⁶ /K | | **Thermal Conductivity** | 15.6 W/m·K | 15.6 W/m·K | 15.6 W/m·K | | **Modulus of Elasticity** | 201 GPa | 201 GPa | 201 GPa | | **Magnetic Permeability** | <1.05 | <1.05 | <1.05 | --- ### **4.0 Mechanical Properties Comparison** | Property | Alloy 800HT (N08811) | Alloy 800H (N08810) | Alloy 800 (N08800) | |----------|---------------------|-------------------|-------------------| | **Tensile Strength** | 450 MPa min | 450 MPa min | 515 MPa min | | **Yield Strength** | 170 MPa min | 170 MPa min | 205 MPa min | | **Elongation** | 30% min | 30% min | 30% min | | **Creep Strength** | **Superior** | Excellent | Good | | **Max Service Temp** | 815°C | 815°C | 650°C | | **Stress Rupture Life** | **Longest** | Long | Moderate | --- ### **5.0 Comprehensive International Standards** **UNS Designations** - **N08811**: Alloy 800HT (Enhanced high-temperature grade) - **N08810**: Alloy 800H (Standard high-temperature grade) - **N08800**: Alloy 800 (Standard grade) **ASTM/ASME Specifications** - **Plate, Sheet, Strip**: ASTM B409 / ASME SB-409 - **Rod, Bar**: ASTM B408 / ASME SB-408 - **Pipe, Tube**: ASTM B407, B163 / ASME SB-407, SB-163 - **Forgings**: ASTM B564 / ASME SB-564 - **Fittings**: ASTM B366 / ASME SB-366 **European Standards** - **EN 10095**: 1.4959 (X8NiCrAlTi32-21 enhanced) - **DIN 17742**: 1.4959 - **AFNOR**: Z8NCT 33.21 **Other National Standards** - **JIS**: NCF 800HT - **GB**: GH0800H (China enhanced) - **ISO 6207**: Nickel alloy specifications --- ### **6.0 Related Alloy Specifications** **Direct Variants in 800 Series** - **Alloy 800 (N08800)**: Standard version with lower carbon - **Alloy 800H (N08810)**: High-carbon version for creep resistance - **Alloy 800HT (N08811)**: Enhanced Al+Ti for maximum stability **Similar Performance Alloys** - **Alloy 801 (N08801)**: Enhanced carburization resistance - **Alloy 802 (N08802)**: Higher carbon for specific applications - **Alloy 840**: Higher chromium for improved oxidation resistance **International Equivalents** - **Incoloy 800HT**: Special Metals Corporation - **NA 15 HT**: British enhanced designation - **Nicrofer 3220 HTi**: ThyssenKrupp enhanced grade --- ### **7.0 Application Spectrum by Specification** **N08811 (Alloy 800HT) Applications** - Critical steam methane reformer outlet headers - Advanced ethylene cracking furnace systems - Nuclear heat exchangers and components - High-stress thermal processing equipment - Aerospace combustion components **N08810 (Alloy 800H) Applications** - Standard reformer and cracker components - High-temperature heat exchangers - Industrial furnace radiant tubes - General high-temperature equipment **N08800 (Alloy 800) Applications** - General chemical processing equipment - Heat treating fixtures - Low-stress high-temperature components - Electrical heating elements --- ### **8.0 Key Differentiating Factors** **Carbon Content Significance** - **N08800**: ≤0.05% C - General purpose - **N08810**: 0.05–0.10% C - Enhanced creep strength - **N08811**: 0.06–0.10% C - Maximum high-temperature performance **Aluminum + Titanium Control** - **N08810**: ≥0.85% Al+Ti - Standard high-temperature stability - **N08811**: ≥1.20% Al+Ti - Enhanced oxidation resistance and strength **Heat Treatment Requirements** - **800HT**: Requires specific solution annealing at 1120–1170°C - **800H/800**: Standard annealing at 980–1065°C --- ### **9.0 Selection Guidelines** **Choose Alloy 800 (N08800) for:** - Temperatures below 650°C (1200°F) - Moderate stress applications - General corrosion resistance requirements - Cost-sensitive projects **Choose Alloy 800H (N08810) for:** - Temperatures 650–815°C (1200–1500°F) - Creep and stress rupture critical applications - Most petrochemical furnace applications - Balanced cost-performance requirements **Choose Alloy 800HT (N08811) for:** - Most demanding high-temperature applications - Maximum oxidation resistance requirements - Critical nuclear components - Extended design life requirements - Superior thermal stability needs --- ### **10.0 Quality & Certification** **Standard Certifications** - PED 2014/68/EU Category - ASME Nuclear Certifications (N, NPT) - ISO 9001 Quality Management - ISO 14001 Environmental Management - NADCAP for aerospace applications **Testing Requirements** - Chemical analysis per heat and product - Mechanical testing per heat treatment lot - Non-destructive examination as specified - High-temperature testing for critical applications - Grain size testing (ASTM 3–6 required for 800HT) **Documentation** - Mill Test Certificates 3.1 or 3.2 - Material test reports with full traceability - Compliance certificates to specified standards - Heat treatment charts and records - NDE reports and certifications --- ### **11.0 Technical Conclusion** The **Alloy 800 series (800/800H/800HT)** represents a carefully engineered family of nickel-iron-chromium alloys designed to meet specific high-temperature performance requirements. While sharing a common base composition, the controlled variations in carbon, aluminum, and titanium content create distinct performance characteristics that make each grade suitable for specific application environments. **Alloy 800HT (N08811)** represents the premium choice for the most demanding high-temperature applications, offering enhanced creep resistance, superior microstructural stability, and optimized oxidation resistance through its carefully controlled chemistry and specialized heat treatment requirements. Understanding the subtle but critical differences between these related specifications enables engineers to select the most appropriate material for their specific service conditions, ensuring optimal performance, reliability, and cost efficiency throughout the component lifecycle. The 800HT specification particularly justifies its selection in applications where extended service life, reduced maintenance, and maximum reliability at extreme temperatures are paramount considerations. --- **Contact Information** For technical specifications, material selection guidance, or custom requirements across the 800 series alloys, please contact our technical sales team.

Packing of 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 1920 gallon liquid totes Special package is available on request.