Incoloy 803 Alloy
High-Temperature, Carburization-Resistant Nickel-Iron-Chromium Alloy
Supplied by Huaxiao-Alloy – Your Trusted Global Alloy Partner
Incoloy® 803 Alloy is a nickel-iron-chromium heat-resistant alloy specifically developed for extreme high-temperature service, where oxidation, carburization, metal dusting, and sulfidation resistance are critical. With controlled aluminum and titanium additions, Incoloy 803 exhibits excellent scale adhesion, structural stability, and long-term creep strength at temperatures up to 1100°C (2010°F).
Huaxiao-Alloy supplies Incoloy 803 Alloy in all product forms, fully compliant with international standards, serving furnace manufacturers, petrochemical plants, power stations, and high-temperature engineering projects worldwide.
1. Incoloy 803 Alloy Overview
Incoloy 803 is designed for continuous service in carburizing, nitriding, and oxidizing atmospheres, outperforming conventional stainless steels and many nickel alloys at elevated temperatures. Its balanced Ni-Cr-Fe matrix combined with Al-Ti micro-alloying provides:
Superior resistance to carbon pickup
Outstanding oxide scale adhesion
Excellent thermal fatigue resistance
Stable mechanical properties over long exposures
This makes Incoloy 803 ideal for industrial furnaces, reformers, ethylene cracking units, and heat treatment equipment.
2. Incoloy 803 Chemical Composition (%)
| Element | Content (%) |
|---|---|
| Nickel (Ni) | 34.0 – 38.0 |
| Chromium (Cr) | 19.0 – 23.0 |
| Iron (Fe) | Balance |
| Aluminum (Al) | 0.15 – 0.60 |
| Titanium (Ti) | 0.15 – 0.60 |
| Carbon (C) | ≤ 0.10 |
| Manganese (Mn) | ≤ 1.50 |
| Silicon (Si) | ≤ 1.00 |
| Sulfur (S) | ≤ 0.015 |
Key Design Feature:
The Al + Ti combination forms a dense, adherent oxide layer that prevents carbon diffusion and metal dusting at high temperature.
3. Mechanical Properties (Typical, Annealed)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 520 MPa |
| Yield Strength (0.2%) | ≥ 240 MPa |
| Elongation | ≥ 30% |
| Hardness | ≤ 200 HB |
| Creep Rupture Strength | Excellent up to 1100°C |
Mechanical properties remain stable during prolonged high-temperature exposure.
4. Physical Properties
| Property | Value |
|---|---|
| Density | 7.95 g/cm³ |
| Melting Range | 1370 – 1400°C |
| Thermal Conductivity | 14.5 W/m·K |
| Electrical Resistivity | 1.05 μΩ·m |
| Thermal Expansion (20–1000°C) | 15.5 μm/m·K |
5. Key Features & Advantages
🔥 Exceptional High-Temperature Stability
Maintains strength and ductility in continuous service above 1000°C.
🛡️ Superior Carburization & Metal Dusting Resistance
Ideal for hydrocarbon processing, reformers, and cracking furnaces.
♨️ Oxidation & Sulfidation Resistance
Excellent scale adherence in air, CO, CO₂, H₂, and sulfur-bearing atmospheres.
🔧 Fabrication Friendly
Can be hot-worked, cold-worked, machined, and welded using standard nickel-alloy practices.
6. Available Product Forms (Huaxiao-Alloy Supply)
Huaxiao-Alloy supplies Incoloy 803 Alloy in all standard and custom forms:
Tubular Products
Seamless pipes
Welded pipes
Precision tubes
Furnace tubes
Radiant tubes
Flat Products
Sheets
Plates
Coils
Strips
Long Products
Round bars
Square bars
Forged bars
Wire rods
Welding wires
Fabricated Components
Furnace fixtures
Retorts
Trays
Flanges
Custom machined parts
7. Standards & Equivalent Grades
| Standard | Designation |
|---|---|
| UNS | N08803 |
| ASTM | B409 / B407 / B829 |
| ASME | SB-409 / SB-407 |
| DIN / EN | Equivalent available on request |
| ISO | Heat-resistant nickel alloy |
📌 Mill Test Certificates (EN 10204 3.1 / 3.2) available
8. Corrosion & Environmental Resistance
Incoloy 803 excels in:
Oxidizing atmospheres
Carburizing environments
Metal dusting conditions
Sulfur-bearing gases
High-carbon potential furnaces
It significantly outperforms 310S, 253MA, and 601 in long-term carburization resistance.
9. Typical Applications
Industrial Furnace Systems
Radiant tubes
Muffle furnaces
Retorts & trays
Furnace rollers
Petrochemical & Refining
Steam reformers
Ethylene cracking furnaces
Hydrogen production units
Power & Energy
High-temperature heat exchangers
Waste heat recovery systems
Metallurgical Industry
Heat treatment fixtures
Continuous annealing lines
10. Fabrication & Welding Guide
Forming
Hot forming: 1150–950°C
Cold forming: Good ductility, intermediate annealing recommended
Heat Treatment
Solution annealing: 1100–1150°C, rapid quench
Welding
GTAW / GMAW / SMAW
Nickel-based filler metals recommended
Preheating not required
11. Quality Control & Certifications
Huaxiao-Alloy guarantees:
Full chemical & mechanical testing
PMI & ultrasonic inspection
Dimensional & surface inspection
EN 10204 3.1 / 3.2 certificates
ISO 9001 quality management
12. Why Choose Huaxiao-Alloy for Incoloy 803?
✔ Direct mill sourcing
✔ Large stock & fast delivery
✔ Custom sizes & machining
✔ Export-ready packaging
✔ Technical selection support
✔ Competitive pricing for bulk orders
📍 Factories: Wuxi · Foshan · Shanghai Baoshan
🌍 Exports: North America · Europe · Middle East · Southeast Asia
Yes. It offers far superior carburization and metal dusting resistance.
Up to 1100°C in continuous service.
Yes, widely used in hydrogen reforming units.
Absolutely. Length, OD, wall thickness can be customized.
Generally non-magnetic in annealed condition.
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