ASTM A182 F5 Blind Flanges | BLRF ASME B16.5
ASTM A182 F5 Blind Flanges are forged chromium-molybdenum alloy steel flanges designed for pressure piping systems operating at elevated temperatures.
F5 is a 5Cr-0.5Mo low-alloy steel grade with the UNS designation K41545. The combination of approximately 4–6% chromium and 0.44–0.65% molybdenum provides improved elevated-temperature strength, oxidation resistance and resistance to high-temperature degradation compared with conventional carbon steel.
ASTM A182 F5 flanges are commonly used in oil refineries, petrochemical plants, chemical-processing equipment, power-generation systems and other high-temperature pressure applications.
We manufacture and supply ASTM A182 F5 forged flanges including Blind Flanges, Weld Neck Flanges, Slip-On Flanges and other ASME B16.5 / B16.47 configurations.
ASTM A182 F5 Material Overview
| Item | Specification |
|---|---|
| Material Standard | ASTM A182 / ASME SA-182 |
| Grade | F5 |
| UNS | K41545 |
| Material Type | Chromium-Molybdenum Low-Alloy Steel |
| Common Description | 5Cr-0.5Mo |
| Chromium | 4.00–6.00% |
| Molybdenum | 0.44–0.65% |
| Main Product | Forged Flanges and Pressure Components |
| Typical Service | Elevated-Temperature Pressure Service |
| Dimensional Standards | ASME B16.5 / ASME B16.47 |
| Common Applications | Refinery, Petrochemical, Chemical and Power Generation |
What Is ASTM A182 F5?
ASTM A182 F5 is a forged low-alloy steel grade intended for high-temperature pressure service.
ASTM A182 covers forged or rolled alloy and stainless steel flanges, forged fittings, valves and related components.
The F5 grade contains substantially more chromium than F11 or F22 Cr-Mo steels and is commonly described as a 5Cr-0.5Mo alloy steel.
Key characteristics include:
- Good elevated-temperature mechanical strength
- Improved oxidation resistance
- Good resistance to high-temperature scaling
- Better performance than carbon steel in selected hot process environments
- Suitable for pressure-containing forged components
- Controlled heat-treatment and hardness requirements
F5 is particularly associated with refinery and petrochemical equipment exposed to elevated temperatures.
ASTM A182 F5 Chemical Composition
Typical ASTM A182 F5 chemical requirements are:
| Element | Composition |
|---|---|
| Carbon, C | 0.15% max |
| Manganese, Mn | 0.30–0.60% |
| Silicon, Si | 0.50% max |
| Phosphorus, P | 0.030% max |
| Sulfur, S | 0.030% max |
| Chromium, Cr | 4.00–6.00% |
| Nickel, Ni | 0.50% max |
| Molybdenum, Mo | 0.44–0.65% |
| Copper, Cu | 0.35% max |
Actual heat chemistry is reported on the Material Test Certificate and shall comply with the applicable ASTM A182 / ASME SA-182 specification.
ASTM A182 F5 Mechanical Properties
Typical minimum room-temperature mechanical requirements include:
| Property | Requirement |
|---|---|
| Tensile Strength, min. | 485 MPa / 70 ksi |
| Yield Strength, min. | 275 MPa / 40 ksi |
| Elongation, min. | 20% |
| Reduction of Area, min. | 35% |
| Brinell Hardness | 143–217 HBW |
Mechanical properties apply to material supplied in the required heat-treated condition.
ASTM A182 F5 Heat Treatment
Heat treatment is critical to achieving the required microstructure, strength and hardness of F5 forgings.
ASTM A182 permits appropriate heat-treatment conditions for F5, including annealing or normalizing and tempering.
For normalized and tempered F5, the typical ASTM requirements include:
- Normalizing / austenitizing temperature: 955°C / 1750°F minimum
- Air cooling after normalizing
- Tempering temperature: 675°C / 1250°F minimum
The final heat-treatment condition should comply with the applicable ASTM A182 edition and project specification.
The allowable design temperature of the completed flange should not be determined from the material heat-treatment temperature.
Actual pressure-temperature rating depends on the applicable piping code, flange standard, pressure class and service conditions.
What Is an ASTM A182 F5 Blind Flange?
A Blind Flange is a solid forged flange without a center bore.
It is used to close the end of:
- Pipelines
- Valve connections
- Pressure-vessel nozzles
- Manifolds
- Process piping branches
Because there is no bore, a blind flange allows the piping system to be isolated while retaining a bolted flange connection that can later be removed for inspection, maintenance or system modification.
Common descriptions include:
- Blind Flange
- BL Flange
- BLRF Flange
- Blind Raised Face Flange
- RTJ Blind Flange
- Blank Flange
For ASME terminology, Blind Flange is preferred over informal descriptions such as blank flange.
ASTM A182 F5 Blind Flange Supply Range
Typical supply capability includes:
| Item | Supply Range |
|---|---|
| Material | ASTM A182 F5 / ASME SA-182 F5 |
| Type | Blind Flange / BLRF |
| Size | NPS 1/2″ through NPS 24″ to ASME B16.5 |
| Large Diameter | NPS 26″ through NPS 60″ to ASME B16.47 |
| Pressure Class | 150, 300, 600, 900, 1500, 2500 |
| Facing | RF, RTJ, FF where applicable |
| Dimensional Standards | ASME B16.5 / ASME B16.47 |
| Inspection | EN 10204 3.1 / 3.2 where specified |
| Manufacturing | Forged / Ring Rolled as applicable |
ASME B16.5 applies to pipe flanges and flanged fittings from NPS 1/2 through NPS 24. Large-diameter flanges from NPS 26 through NPS 60 are generally specified to ASME B16.47.
ASME B16.5 F5 BLRF Flanges
BLRF means:
Blind Raised Face Flange
The raised-face sealing surface is commonly used with spiral wound, graphite and other suitable flange gaskets depending on the piping specification.
Typical descriptions include:
ASTM A182 F5 Blind RF Flange, ASME B16.5, Class 150
or:
ASTM A182 F5 BLRF, NPS 8″, Class 300, ASME B16.5
For higher-pressure and selected refinery applications, Ring Type Joint Blind Flanges may also be specified.
ASTM A182 F5 Flange Types
In addition to Blind Flanges, available F5 forged flange types can include:
- ASTM A182 F5 Weld Neck Flange
- ASTM A182 F5 Blind Flange
- ASTM A182 F5 Slip-On Flange
- ASTM A182 F5 Socket Weld Flange
- ASTM A182 F5 Threaded Flange
- ASTM A182 F5 Long Weld Neck Flange
- RF Flange
- RTJ Flange
- Custom Forged Flanges
Each flange should be ordered according to the correct material specification, dimensional standard, pressure class and facing.
ASTM A182 F5 vs F9
F5 and F9 are both chromium-molybdenum low-alloy steels used for elevated-temperature service.
| Item | ASTM A182 F5 | ASTM A182 F9 |
|---|---|---|
| Common Alloy Description | 5Cr-0.5Mo | 9Cr-1Mo |
| Chromium | 4–6% | Approx. 8–10% |
| Molybdenum | 0.44–0.65% | Approx. 0.9–1.1% |
| Strength Level | High | Higher |
| Oxidation Resistance | Good | Higher |
| Typical Service | Refinery / Petrochemical | More severe high-temperature service |
Material selection should be based on the piping design code and actual process conditions.
International Material Comparison
ASTM A182 F5 is commonly compared with European Cr-Mo grades such as:
- 12CrMo19-5
- EN / W.Nr. 1.7362
These materials have similar 5Cr-Mo alloy concepts.
However, ASTM, ASME and EN grades are controlled by different chemistry, heat treatment, mechanical testing and product requirements.
They should therefore be treated as comparable material grades, not automatically interchangeable equivalents.
Typical Applications
ASTM A182 F5 flanges are commonly used in:
- Oil refineries
- Petrochemical plants
- Chemical-processing systems
- Hydrogen-processing units
- Hot hydrocarbon piping
- High-temperature process piping
- Power plants
- Heat exchangers
- Pressure vessels
- Valve and pump connections
- High-temperature steam and process systems
Inspection and Certification
ASTM A182 F5 forged flanges can be supplied with:
- EN 10204 Type 3.1 MTC
- EN 10204 Type 3.2 when specified
- Chemical Analysis
- Tensile Testing
- Yield Strength Testing
- Hardness Testing
- Heat-Treatment Records
- PMI
- Dimensional Inspection
- Visual Inspection
- UT where specified
- MT where specified
- Third-Party Inspection
- Full Heat-Number Traceability
Additional inspection and testing can be arranged according to project specifications.
How to Order ASTM A182 F5 Blind Flanges
A complete inquiry should include:
- Material grade
- Flange type
- Nominal pipe size
- Pressure class
- Facing
- Dimensional standard
- Quantity
- Inspection requirement
Example 1
ASTM A182 F5 Blind Flange, NPS 3″, Class 300, RF, ASME B16.5
Example 2
ASTM A182 F5 BLRF Flange, NPS 16″, Class 150, ASME B16.5
Example 3
ASTM A182 F5 Blind Flange, NPS 8″, Class 600, RTJ, ASME B16.5
Frequently Asked Questions
What is ASTM A182 F5?
ASTM A182 F5 is a 5Cr-0.5Mo low-alloy steel forging grade used for flanges, forged fittings, valves and related components in elevated-temperature pressure service.
What is an F5 BLRF flange?
BLRF means Blind Raised Face Flange.
An ASTM A182 F5 BLRF is a forged F5 Blind Flange with a Raised Face sealing surface.
What is the UNS number for ASTM A182 F5?
The UNS designation commonly associated with ASTM A182 F5 is K41545.
What size does ASME B16.5 cover?
ASME B16.5 covers pipe flanges and flanged fittings from NPS 1/2 through NPS 24.
For larger flanges, ASME B16.47 is commonly used.
What are the typical applications of F5 flanges?
F5 forged flanges are commonly used in refinery, petrochemical, chemical-processing and other elevated-temperature pressure piping systems.
Is F5 the same as 1.7362?
F5 and EN 1.7362 / 12CrMo19-5 are commonly compared because of their similar Cr-Mo alloy systems, but they are controlled by different material standards and should not automatically be considered fully interchangeable.
ASTM A182 F5 Blind Flange Manufacturer
We manufacture and supply ASTM A182 F5 / ASME SA-182 F5 forged flanges for refinery, petrochemical, chemical-processing and elevated-temperature pressure applications.
Available products include:
- ASTM A182 F5 Blind Flange
- ASTM A182 F5 BLRF Flange
- ASTM A182 F5 RTJ Blind Flange
- ASTM A182 F5 Weld Neck Flange
- ASTM A182 F5 Slip-On Flange
- ASTM A182 F5 Socket Weld Flange
- ASME B16.5 F5 Flanges
- ASME B16.47 F5 Flanges
For quotation, please provide the flange type, NPS size, pressure class, facing, quantity and inspection requirements.
