ASTM B564 UNS N06601 Weld Neck Flange | Alloy 601 2.4851
ASTM B564 UNS N06601 flanges are forged nickel-chromium-iron-aluminum alloy flanges designed for high-temperature process piping and thermal equipment. Alloy 601 is particularly valued for its excellent resistance to high-temperature oxidation, good strength, and ability to maintain a protective oxide scale during repeated heating and cooling cycles.
We manufacture and supply ASTM B564 / ASME SB-564 UNS N06601 weld neck, long weld neck, blind, slip-on and socket weld flanges to ASME B16.5 and ASME B16.47, with RF, FF and RTJ facing as applicable and EN 10204 3.1 certification.
ASTM B564 N06601 Flange Specification
| Item | Specification |
|---|---|
| Material Standard | ASTM B564 / ASME SB-564 |
| UNS | N06601 |
| Material | Alloy 601/Inconel 601 |
| EN / W.Nr. | 2.4851 |
| Material Family | Nickel-Chromium-Iron-Aluminum Alloy |
| Primary Flange Type | Weld Neck Flange |
| Other Flange Types | Blind / Slip-On / Socket Weld / Long Weld Neck / Threaded |
| Flange Standards | ASME B16.5 / ASME B16.47 |
| Facing | RF / FF / RTJ as applicable |
| Condition | Annealed |
| Certification | EN 10204 3.1 / 3.2 when specified |
What Is ASTM B564 UNS N06601?
ASTM B564 UNS N06601 is a nickel-chromium-iron alloy forging grade containing aluminum for enhanced high-temperature oxidation resistance.
ASTM B564 Inconel 601 is a nickel-chromium alloy used for applications that require resistance to corrosion and heat. This nickel alloy stands out due to its resistance to high temperature oxidation, remaining highly resistant to oxidation through 2200° F.
The principal alloying system is:
Ni + Cr + Fe + Al
This combination provides:
- Excellent high-temperature oxidation resistance
- Good resistance to thermal cycling
- Good high-temperature mechanical strength
- Resistance to many furnace atmospheres
- Good fabrication and welding characteristics
- Useful corrosion resistance in many process environments
The principal material designations are:
| System | Designation |
|---|---|
| ASTM | B564 UNS N06601 |
| ASME | SB-564 UNS N06601 |
| UNS | N06601 |
| EN / W.Nr. | 2.4851 |
| Material | Alloy 601 |
ASTM B564 N06601 Chemical Composition
| Element | UNS N06601 |
|---|---|
| Nickel, Ni | 58.0–63.0% |
| Chromium, Cr | 21.0–25.0% |
| Iron, Fe | Balance |
| Aluminum, Al | 1.0–1.7% |
| Carbon, C | 0.10% max |
| Manganese, Mn | 1.00% max |
| Silicon, Si | 0.50% max |
| Sulfur, S | 0.015% max |
| Copper, Cu | 1.00% max |
The relatively high chromium content provides oxidation resistance, while aluminum promotes formation of a stable and tightly adherent protective oxide layer at elevated temperatures.
Actual heat chemistry is reported on the Material Test Certificate.
ASTM B564 N06601 Mechanical Properties
Typical minimum room-temperature mechanical requirements for annealed UNS N06601 forgings include:
| Property | Minimum Requirement |
|---|---|
| Tensile Strength | 550 MPa / 80 ksi |
| Yield Strength | 205 MPa / 30 ksi |
| Elongation | 30% |
Actual mechanical test results are reported on the supplied MTC.
For pressure design, allowable pressure-temperature ratings shall follow the applicable design code and flange standard rather than general material-property values alone.
Heat Treatment of ASTM B564 N06601
ASTM B564 N06601 forgings are supplied in the required annealed condition.
Controlled heat treatment is important for maintaining:
- Ductility
- Mechanical properties
- Oxidation resistance
- Fabrication performance
- Stable high-temperature service behavior
Heat-treatment records can be supplied when specified by the purchase order or project ITP.
High-Temperature Oxidation Resistance
One of the most important characteristics of UNS N06601 is its excellent resistance to oxidation at elevated temperatures.
The chromium and aluminum additions promote formation of a tightly adherent protective oxide scale, helping the material resist:
- Oxidation
- Scale spalling
- Repeated heating and cooling
- Thermal cycling
- Hot-gas exposure
- Many furnace atmospheres
Alloy 601 is widely selected for components operating in very high-temperature oxidizing environments.
In suitable oxidizing conditions, the alloy retains strong oxidation resistance at temperatures approaching approximately 1200°C / 2200°F.
This temperature represents a material oxidation-resistance capability and should not be interpreted as a universal allowable design temperature for a pressure flange.
Actual flange pressure and temperature limits depend on:
- Applicable design code
- Pressure class
- Flange dimensions
- Operating atmosphere
- Mechanical loading
- Service environment
Sulfur-Bearing Environments
UNS N06601 performs well in many high-temperature environments, but it is not generally selected for strongly reducing sulfur-bearing atmospheres.
Material suitability should be evaluated carefully when service involves:
- Sulfur compounds
- Reducing furnace atmospheres
- Carbon activity
- Process contaminants
- High-temperature gas chemistry
The actual furnace or process atmosphere can significantly affect material performance.
ASTM B564 N06601 Weld Neck Flange
The weld neck flange is one of the most suitable flange types for demanding high-temperature piping systems.
A weld neck flange uses a long tapered hub and butt-weld connection to the pipe, providing a gradual transition between the pipe wall and flange body.
This design helps distribute stresses caused by:
- Internal pressure
- Thermal expansion
- Temperature cycling
- Pipe loads
- Vibration
- Repeated heating and cooling
Available configurations include:
WNRF – Weld Neck Raised Face
WNRTJ – Weld Neck Ring Type Joint
The flange bore can be machined according to the specified pipe schedule or wall thickness.
A typical ordering description is:
ASTM B564 UNS N06601 WNRF Flange, NPS 6, SCH 40S, Class 600, ASME B16.5
Available Alloy 601 Flange Types
| Flange Type | Typical Connection / Function |
|---|---|
| Weld Neck | Butt-welded to pipe |
| Long Weld Neck | Extended neck for vessel or equipment connection |
| Blind | Closes a piping or equipment opening |
| Slip-On | Pipe inserted and fillet welded |
| Socket Weld | Socket connection for small-bore piping |
| Threaded | Threaded connection when specified |
Facing options can include:
- Raised Face – RF
- Ring Type Joint – RTJ
- Flat Face – FF where applicable
The required flange type, facing, bore and pressure class should be clearly stated in the purchase specification.
ASME B16.5 Size & Pressure Classes
ASME B16.5 covers standard pipe flanges in the following ranges:
| Pressure Class | Size Range |
|---|---|
| Class 150 | NPS 1/2–24 |
| Class 300 | NPS 1/2–24 |
| Class 400 | NPS 1/2–24 |
| Class 600 | NPS 1/2–24 |
| Class 900 | NPS 1/2–24 |
| Class 1500 | NPS 1/2–24 |
| Class 2500 | NPS 1/2–12 |
Class 2500 should therefore not be described as covering the full NPS 1/2–24 range.
ASME B16.47 Large-Diameter Flanges
For larger diameters, ASME B16.47 covers:
NPS 26–60
with:
Class 75 / 150 / 300 / 400 / 600 / 900
Large-diameter UNS N06601 flanges can be manufactured to ASME B16.47 or project-specific dimensions where applicable.
Alloy 601 vs Alloy 600 Flanges
Alloy 601 and Alloy 600 are both nickel-chromium alloys, but their compositions and primary service strengths differ.
| Item | Alloy 601 / N06601 | Alloy 600 / N06600 |
|---|---|---|
| Ni | 58–63% | Higher |
| Cr | 21–25% | Lower |
| Al | 1.0–1.7% | Low |
| High-Temperature Oxidation | Excellent | Good |
| Thermal Cycling Resistance | Very Good | Good |
| Main Positioning | Furnace / thermal processing | General corrosion and heat service |
The aluminum addition is one of the main reasons Alloy 601 offers stronger oxidation resistance in many high-temperature applications.
Neither alloy is universally superior; material selection depends on service temperature, atmosphere, mechanical requirements and corrosion conditions.
Applications
ASTM B564 N06601 flanges are commonly used in:
- Industrial furnaces
- Heat-treatment furnaces
- Furnace piping
- Burner systems
- Petrochemical heaters
- Thermal-processing equipment
- Power-generation equipment
- Hot-gas piping
- Radiant heating systems
- Chemical-processing equipment
- Pollution-control equipment
- High-temperature process equipment
UNS N06601 is particularly useful where repeated heating and cooling make oxidation resistance and oxide-scale stability important.
Related UNS N06601 Products
A complete N06601 material system can include:
| Component | Typical Specification |
|---|---|
| Forged Flange | ASTM B564 UNS N06601 |
| Seamless Pipe / Tube | ASTM B167 UNS N06601 |
| Plate / Sheet | ASTM B168 UNS N06601 |
| Rod / Bar | ASTM B166 UNS N06601 |
ASTM B564 N06601 flanges can be supplied together with matching N06601 pipe, tube, plate and bar according to project requirements.
Inspection & Certification
ASTM B564 N06601 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 examination
- Flange-facing inspection
- RTJ groove inspection when applicable
- Hardness testing when specified
- PT when required
- UT when specified
- Third-party inspection
- Full heat-number traceability
Inspection requirements can be specified according to the material standard, flange standard and project ITP.
Frequently Asked Questions
What is ASTM B564 UNS N06601?
ASTM B564 UNS N06601 is a nickel-chromium-iron-aluminum forging alloy used for high-temperature flanges and other forged pressure components.
It is particularly valued for oxidation resistance and stability during thermal cycling.
Why is Alloy 601 used for high-temperature flanges?
Alloy 601 contains high chromium and aluminum, which help form a tightly adherent protective oxide scale at elevated temperatures.
This gives the material strong resistance to oxidation and scale spalling during repeated heating and cooling.
What are the minimum mechanical properties of N06601 forgings?
Typical minimum room-temperature requirements include approximately 550 MPa tensile strength, 205 MPa yield strength and 30% elongation in the annealed condition.
What size range does ASME B16.5 cover?
ASME B16.5 covers NPS 1/2–24 for Class 150 through Class 1500 and NPS 1/2–12 for Class 2500.
What is the difference between Alloy 601 and Alloy 600 flanges?
Alloy 601 contains more chromium and a deliberate aluminum addition, giving it stronger high-temperature oxidation resistance in many furnace and thermal-processing environments.
Alloy 600 provides broad heat and corrosion resistance but has a different alloy design and service positioning.
ASTM B564 UNS N06601 Flange-Alloy 601
ASTM B564 N06601 Flange Manufacturer
We manufacture and supply ASTM B564 / ASME SB-564 UNS N06601 forged flanges for furnace systems, thermal-processing equipment, petrochemical heaters, power-generation and other high-temperature applications.
Available products include:
Weld Neck / WNRF / WNRTJ / Long Weld Neck / Blind / Slip-On / Socket Weld Flanges
with ASME B16.5 and ASME B16.47 dimensions, PMI, NDE and EN 10204 certification when required.
For quotation, please specify:
Material + Flange Type + NPS + Pipe Schedule/WT + Pressure Class + Facing + Standard + Quantity + Inspection Requirements
Example:
ASTM B564 UNS N06601 WNRF Flange, NPS 6, SCH 40S, Class 600, RF, ASME B16.5, EN 10204 3.1
Other N06601 Products
ASTM B167 Alloy 601 UNS N06601 Nickel Alloy Tube
