ASTM B564 UNS N08800 Alloy 800 Flange | ASME B16.5
ASTM B564 UNS N08800 Alloy 800 flanges are forged nickel-iron-chromium alloy flanges used in heat-resistant and corrosion-resistant pressure piping systems. Alloy 800 combines approximately 30–35% nickel and 19–23% chromium with an iron base, providing good strength, oxidation resistance and structural stability at elevated temperatures.
We manufacture and supply ASTM B564 / ASME SB-564 Alloy 800 weld neck flanges (WNRF), blind flanges, slip-on flanges and other forged flanges to ASME B16.5, ASME B16.47 and project-specific requirements.
ASTM B564 Alloy 800 Flange Specification
| Item | Specification |
|---|---|
| Material Standard | ASTM B564 / ASME SB-564 |
| UNS | N08800 |
| Material | Alloy 800 |
| Commercial Name | INCOLOY® alloy 800 |
| Material Family | Nickel-Iron-Chromium |
| Main Product | Forged Flange |
| Flange Types | WN / Blind / Slip-On / SW / Threaded |
| ASME B16.5 Size | NPS 1/2–24 |
| B16.5 Classes | 150 / 300 / 400 / 600 / 900 / 1500 |
| Class 2500 | NPS 1/2–12 |
| Large Diameter | ASME B16.47 where applicable |
| Certification | EN 10204 3.1 / 3.2 when specified |
What Is ASTM B564 UNS N08800?
ASTM B564 covers nickel-alloy forgings, including UNS N08800 Alloy 800.
UNS N08800 is a nickel-iron-chromium alloy designed to maintain an austenitic structure while providing a useful combination of:
- High-temperature strength
- Oxidation resistance
- Carburization resistance
- Structural stability during elevated-temperature exposure
- Good resistance to many corrosive environments
- High resistance to chloride stress-corrosion cracking in many service conditions
- Good fabrication and welding characteristics
ASTM B564 normally positions N08800 for service temperatures up to and including 593°C / 1100°F.
For service above this temperature where creep and rupture resistance become important, UNS N08810 Alloy 800H or UNS N08811 Alloy 800HT-type material is normally selected.
Alloy 800 Chemical Composition
| Element | UNS N08800 |
|---|---|
| Nickel, Ni | 30.0–35.0% |
| Chromium, Cr | 19.0–23.0% |
| Iron, Fe | 39.5% min. |
| Carbon, C | 0.10% max |
| Manganese, Mn | 1.50% max |
| Silicon, Si | 1.00% max |
| Sulfur, S | 0.015% max |
| Copper, Cu | 0.75% max |
| Aluminum, Al | 0.15–0.60% |
| Titanium, Ti | 0.15–0.60% |
The high nickel content helps maintain an austenitic structure and contributes to resistance to chloride-ion stress-corrosion cracking.
Chromium contributes to oxidation and general corrosion resistance, while aluminum and titanium support high-temperature stability.
ASTM B564 N08800 Mechanical Properties
For annealed UNS N08800 forgings, ASTM B564 minimum room-temperature mechanical properties are typically:
| Property | Minimum Requirement |
|---|---|
| Tensile Strength | 517 MPa / 75 ksi |
| Yield Strength, 0.2% | 207 MPa / 30 ksi |
| Elongation | 30% |
Actual mill test values may be higher than the ASTM minimums and should be confirmed from the supplied Material Test Certificate.
Values such as 600 MPa tensile or 295 MPa yield strength should therefore be presented as actual or typical production values when supported by an MTC, not as the ASTM B564 minimum requirement.
Physical Properties of Alloy 800
| Property | Typical Value |
|---|---|
| Density | 7.94 g/cm³ |
| Melting Range | 1357–1385°C |
For a flange purchasing page, these physical properties are generally more relevant than electrical or thermal-property tables.
Alloy 800 vs 800H vs 800HT
The 800-series alloys have similar Ni-Cr-Fe chemistry but are optimized for different temperature regimes.
| Item | Alloy 800 | Alloy 800H | Alloy 800HT |
|---|---|---|---|
| UNS | N08800 | N08810 | N08811 |
| Ni | 30–35% | 30–35% | 30–35% |
| Cr | 19–23% | 19–23% | 19–23% |
| Carbon | ≤0.10% | 0.05–0.10% | 0.06–0.10% |
| Grain Size Control | Not specifically required | Controlled | Controlled |
| Al + Ti | 0.30–1.20% | 0.30–1.20% | 0.85–1.20% |
| ASTM B564 Positioning | Normally ≤593°C | Above 593°C where creep resistance is required | Higher-temperature creep service |
593°C / 1100°F should not be interpreted as a universal maximum allowable temperature for every Alloy 800 component.
It is ASTM B564’s normal grade-selection boundary between N08800 and the creep-strength-controlled N08810/N08811 grades.
Actual allowable design temperature and pressure must follow the applicable ASME Code and material allowable stresses.
ASTM B564 Alloy 800 Weld Neck Flange
A UNS N08800 weld neck raised face flange (WNRF) is a forged Alloy 800 flange with a tapered hub that is butt-welded directly to the pipe.
Advantages include:
- Gradual stress transition from pipe to flange
- Strong full-penetration welded connection
- Good performance under thermal and pressure cycling
- Suitable for critical process piping
- RF or RTJ sealing surfaces as applicable
Typical Alloy 800 WNRF applications include:
- Chemical-processing equipment
- Petrochemical plants
- Process heaters
- Furnace connections
- Heat-treatment systems
- High-temperature process piping
- Steam and thermal systems
- Industrial pressure equipment
ASME B16.5 & B16.47 Dimensions
The flange dimensional standard depends on size and pressure class.
| Standard | Size / Rating |
|---|---|
| ASME B16.5-2025 | NPS 1/2–24, Class 150–1500 |
| ASME B16.5 Class 2500 | NPS 1/2–12 |
| ASME B16.47-2025 | NPS 26–60, Class 75–900 |
Our typical Alloy 800 flange supply can include sizes up to NPS 48, with B16.5, B16.47 or project-specific dimensions selected according to size and design requirements.
Large-diameter products should not be described simply as “ASME B16.5 48-inch flanges.”
Available Alloy 800 Flange Types
We supply:
- Weld Neck Flange / WNRF
- Blind Flange
- Slip-On Flange
- Socket Weld Flange
- Threaded Flange
- Lap Joint Flange
- Reducing Flange
- Raised Face / RF
- Ring Type Joint / RTJ
- Custom forged flanges
EN 1092-1 or project-specific dimensions can also be evaluated when required.
High-Temperature & Corrosion Performance
Alloy 800 is particularly valued for its resistance to elevated-temperature degradation.
Important characteristics include:
- Oxidation resistance
- Carburization resistance
- Resistance to certain nitriding environments
- High-temperature structural stability
- Resistance to many aqueous corrosive environments
- High resistance to chloride stress-corrosion cracking compared with many common austenitic alloys
Material suitability still depends on temperature, process chemistry, concentration, contaminants, pressure and design life.
Alloy 800 should not be described as universally resistant to all reducing acids or chloride environments.
Inspection & Certification
ASTM B564 Alloy 800 flanges can be supplied with:
- EN 10204 Type 3.1 MTC
- EN 10204 Type 3.2 when specified
- Heat chemical analysis
- Mechanical test results
- Heat-treatment records
- PMI
- Dimensional inspection
- Visual inspection
- Ultrasonic examination as applicable
- Dye penetrant examination when specified
- Third-party inspection
- Full heat-number traceability
Actual inspection requirements should be specified in the enquiry and purchase order.
Related Alloy 800 Products
For complete UNS N08800 Alloy 800 piping systems, related material specifications include:
| Product | Related Specification |
|---|---|
| Forged Flange | ASTM B564 N08800 |
| Seamless Pipe & Tube | ASTM B407 Alloy 800 |
| Plate / Sheet / Strip | ASTM B409 Alloy 800 |
| Butt-Weld Fittings | ASTM B366 Alloy 800 |
| Bar / Rod | ASTM B408 Alloy 800 |
Related higher-temperature or alternative nickel-alloy products include:
- Alloy 800H / UNS N08810
- Alloy 800HT / UNS N08811
- ASTM B564 Alloy 825 / UNS N08825 Flanges
- ASTM B564 Alloy 625 Flanges
- ASTM B564 Alloy 600 Flanges
Frequently Asked Questions
What is ASTM B564 UNS N08800?
ASTM B564 UNS N08800 is the forging specification and UNS designation for Alloy 800 nickel-iron-chromium material used for forged pressure components such as flanges.
Is Alloy 800 the same as Incoloy 800?
UNS N08800 is the standardized material designation. INCOLOY® alloy 800 is a registered trade name associated with Special Metals.
In commercial enquiries, “Incoloy 800” and “Alloy 800” commonly refer to UNS N08800.
What is the difference between Alloy 800 and Alloy 800H?
Alloy 800 is UNS N08800, while Alloy 800H is UNS N08810.
ASTM B564 normally positions N08800 up to 593°C / 1100°F. Above this temperature, where creep and stress-rupture strength are important, N08810 or N08811 is normally selected.
Can Alloy 800 be used above 593°C?
Potentially, depending on the design code and service conditions.
However, ASTM B564 normally directs higher-temperature creep/rupture applications toward Alloy 800H or 800HT-type grades, so material selection must follow the governing ASME design requirements.
What standard covers Alloy 800 flange dimensions?
ASME B16.5 covers standard pipe flanges from NPS 1/2–24, while ASME B16.47 covers large-diameter flanges from NPS 26–60.
ASTM B564 Alloy 800 Flange Manufacturer
We manufacture and supply ASTM B564 / ASME SB-564 UNS N08800 Alloy 800 forged flanges for chemical, petrochemical, thermal-processing and high-temperature industrial projects.
Available products include WNRF, blind, slip-on, socket-weld, threaded and RTJ flanges, with customized dimensions, PMI, NDE, EN 10204 certification and third-party inspection when required.
For quotation, please specify:
Material + UNS + Flange Type + NPS + Pressure Class + Facing + Standard + Quantity + Inspection Requirements
Example:
ASTM B564 UNS N08800, WNRF, NPS 6, Class 600, RF, ASME B16.5
