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ASME B16.47 Series A Class 900 Welding Neck Flanges
Material: Carbon Steel, Stainless Steel, Alloy Steel, Duplex Stainless Steel
Thickness: According to ASME B16.47 Series A Class 900
Standard: ASME B16.47 Series A
Pressure Class: Class 900
Flange Type: Welding Neck Flange
Flange Face Type: Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ) upon request
Connection: Butt Weld
Manufacturing Process: Forging and Machining
ASME B16.47 Series A Class 900 Welding Neck Flanges are heavy-duty large-diameter forged flanges designed for demanding piping systems requiring high strength, reliable sealing, and excellent performance under high pressure and temperature.
The flange features a long tapered hub and is butt welded directly to the pipe. This structure provides a smooth stress transition between the flange and pipe, helping reduce stress concentration and improve fatigue resistance.
These flanges are commonly used in oil and gas, petrochemical, power generation, marine, and chemical processing applications. The reference page specifically notes their suitability for oil transportation pipelines, ship piping systems, and chemical raw-material transport.
ASME B16.47 Series A Class 900 Welding Neck Flange Descriptions
ASME B16.47 Series A Class 900 Welding Neck Flanges are designed for large-diameter piping systems operating under demanding pressure and temperature conditions.
A Welding Neck Flange has a long tapered neck that transitions gradually into the pipe. The flange is connected by butt welding, creating a strong and continuous joint.
This design improves structural stability and helps distribute stress more evenly across the connection.
The reference page describes Welding Neck Flanges as high-neck flanges with strong structural performance, good sealing, corrosion resistance, and the ability to withstand high temperature and pressure.
Product Parameters
| Parameter | Description |
|---|---|
| Product Name | ASME B16.47 Series A Class 900 Welding Neck Flange |
| Standard | ASME B16.47 Series A |
| Pressure Rating | Class 900 |
| Size Range | NPS 26" – NPS 48" |
| Flange Type | Welding Neck Flange |
| Connection | Butt Weld |
| Flange Facing | RF, FF, RTJ upon request |
| Material | Carbon Steel, Stainless Steel, Alloy Steel, Duplex Stainless Steel |
| Manufacturing | Forging + Heat Treatment + CNC Machining |
| Surface Treatment | Anti-rust oil, painting, galvanizing or customized coating |
| Inspection | Dimensional Inspection, Visual Inspection, UT, MT, PMI, Hardness Testing |
| Application | Oil & Gas, Petrochemical, Chemical Processing, Power Generation, Marine and Industrial Pipelines |
ASME B16.47 Series A Class 900 Welding Neck Flange Dimensions
Class 900 Dimensions | ASME B16.47 Series A Flange
| Nominal Pipe Size | Outside Diameter (O) | Bolt Circle (W) | Raised Face Diameter (R) | Number of Holes | Diameter of Holes | Bore (B) | Top of Hub (A) | Hub Diameter (X) | Minimum Fillet Radius (r) | Minimum Thickness (T) | Length Thru Hub (Y) | Approx. Weight (lbs) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 26 | 42.75 | 37.50 | 29.50 | 20 | 2.88 | Specified by purchaser | 26.00 | 30.50 | 0.44 | 5.50 | 11.25 | 1525 |
| 28 | 46.00 | 40.25 | 31.50 | 20 | 3.12 | Specified by purchaser | 28.00 | 32.75 | 0.50 | 5.62 | 11.75 | 1810 |
| 30 | 48.50 | 42.75 | 33.75 | 20 | 3.12 | Specified by purchaser | 30.00 | 35.00 | 0.50 | 5.88 | 12.25 | 2120 |
| 32 | 51.75 | 45.50 | 36.00 | 20 | 3.38 | Specified by purchaser | 32.00 | 37.25 | 0.50 | 6.25 | 13.00 | 2545 |
| 34 | 55.00 | 48.25 | 38.00 | 20 | 3.62 | Specified by purchaser | 34.00 | 39.62 | 0.56 | 6.50 | 13.75 | 2970 |
| 36 | 57.50 | 50.75 | 40.25 | 20 | 3.62 | Specified by purchaser | 36.00 | 41.88 | 0.56 | 6.75 | 14.25 | 3395 |
| 38 | 57.50 | 50.75 | 43.25 | 20 | 3.62 | Specified by purchaser | 38.00 | 42.25 | 0.75 | 7.50 | 13.88 | 3385 |
| 40 | 59.50 | 52.75 | 45.75 | 24 | 3.62 | Specified by purchaser | 40.00 | 44.38 | 0.81 | 7.75 | 14.31 | 3620 |
| 42 | 61.50 | 54.75 | 47.75 | 24 | 3.62 | Specified by purchaser | 42.00 | 46.31 | 0.81 | 8.12 | 14.62 | 3960 |
| 44 | 64.88 | 57.62 | 50.00 | 24 | 3.88 | Specified by purchaser | 44.00 | 48.62 | 0.88 | 8.44 | 15.38 | 4300 |
| 46 | 68.25 | 60.50 | 52.50 | 24 | 4.12 | Specified by purchaser | 46.00 | 50.88 | 0.88 | 8.88 | 16.18 | 4640 |
| 48 | 70.25 | 62.50 | 54.50 | 24 | 4.12 | Specified by purchaser | 48.00 | 52.88 | 0.94 | 9.19 | 16.50 | 4980 |
Notes:
All dimensions are in inches.
These flanges are furnished with a 1/4" Raised Face unless otherwise specified.
Bore dimensions are specified by the purchaser.
Customized flange facings, bores, coatings, markings, and machining are available.
Welding Neck Flange
A Welding Neck Flange is characterized by its long tapered hub and butt-weld connection.
The hub gradually transfers mechanical stress from the flange body to the pipe, helping reduce stress concentration around the weld area.
This makes Welding Neck Flanges suitable for:
High-pressure piping
High-temperature systems
Cyclic loading
Vibration
Hazardous process media
Large-diameter industrial pipelines
The reference page notes that Welding Neck Flanges are commonly used where high structural strength, reliable sealing, corrosion resistance, and resistance to high pressure and temperature are required.
ASME B16.47 FLANGE CLASSES
Choose The pressure class below
ASME B16.47 Series A
| Welding Neck Flanges | Blind Flanges |
|---|---|
| Class 150 | Class 150 |
| Class 300 | Class 300 |
| Class 400 | Class 400 |
| Class 600 | Class 600 |
| Class 900 | Class 900 |
ASME B16.47 Series B
| Welding Neck Flanges | Blind Flanges |
|---|---|
| Class 75 | Class 75 |
| Class 150 | Class 150 |
| Class 300 | Class 300 |
| Class 400 | Class 400 |
| Class 600 | Class 600 |
| Class 900 | Class 900 |
Advantages of ASME B16.47 Series A Class 900 Welding Neck Flange
High Structural Strength
The tapered hub provides excellent stress distribution and a strong pipe-to-flange connection.
Reliable Sealing
Precision-machined sealing surfaces provide stable gasket contact and dependable sealing.
Good Fatigue Resistance
The butt-welded connection helps reduce stress concentration caused by vibration and pressure fluctuations.
Suitable for Severe Service
Class 900 Welding Neck Flanges are suitable for demanding piping systems involving high pressure and elevated temperatures.
Multiple Material Options
Carbon steel, stainless steel, alloy steel, and duplex stainless steel are available.
Applications
Oil and Gas Industry
Used in oil transmission pipelines, processing facilities, compressor stations, and refinery systems.
Petrochemical Industry
Suitable for process piping, reactors, pressure vessels, heat exchangers, pumps, and valves.
Chemical Processing
Used for transporting chemical raw materials and other demanding process media.
Power Generation
Applied in high-pressure process piping and power generation systems.
Marine and Shipbuilding
Used in ship pipeline systems and marine industrial applications.
Industrial Piping
Suitable for heavy industrial plants, pressure equipment, machinery, and critical large-diameter pipeline systems.
PRODUCTION PROCESS
Our ASME B16.47 Series A Class 900 Welding Neck Flanges are manufactured through a controlled production process.
Raw Material Inspection → Cutting → Heating → Forging → Heat Treatment → Rough Machining → CNC Machining → Drilling → Beveling → Inspection → Surface Treatment → Marking → Packing
Each production stage is controlled to ensure accurate dimensions, stable material properties, correct bolt-hole arrangements, and reliable sealing surfaces.
Why Choose Us
Experienced Manufacturer
We specialize in forged flange manufacturing for industrial piping systems.
Reliable Quality
Each flange is inspected before shipment.
Multiple Material Options
Carbon steel, stainless steel, alloy steel, and duplex stainless steel are available.
Custom Manufacturing
Customized sizes, bores, facings, coatings, and markings can be supplied.
International Supply
We supply flange products to customers in different industries and global markets.
COMPANY PROFILE
Shanxi HongKai Forging Co., Ltd. is located in Dingxiang County, Shanxi Province, China, an important manufacturing base for forged flanges.
We specialize in the production of forged flanges and industrial forging products for international piping and engineering projects.
Our manufacturing capabilities include:
Forging, Heat Treatment, CNC Machining, Drilling, Testing, Surface Treatment, Marking, Packaging and Shipment.
We manufacture Welding Neck Flanges, Blind Flanges, Slip On Flanges, Socket Weld Flanges, Threaded Flanges, Lap Joint Flanges, and customized forged flanges.
Our products can be supplied according to:
ASME / ANSI / EN / DIN / JIS / AWWA / BS and other international standards.
Available materials include carbon steel, stainless steel, alloy steel, duplex stainless steel, and special material grades.
FAQ
What is an ASME B16.47 Series A Class 900 Welding Neck Flange?
It is a large-diameter flange with a tapered hub that is butt welded directly to the pipe and manufactured according to ASME B16.47 Series A Class 900 dimensional requirements.
What sizes are available?
The reference table covers NPS 26" to NPS 48".
What does Class 900 mean?
Class 900 is an ASME pressure-temperature class designation. Actual allowable working pressure depends on material, temperature, gasket, bolting, and overall piping-system design.
What materials are available?
Common materials include carbon steel, stainless steel, alloy steel, and duplex stainless steel.
What flange facing is normally supplied?
The reference page states that these flanges are furnished with a 1/4" Raised Face unless otherwise specified.
Why use a Welding Neck Flange?
Its tapered hub and butt-welded connection provide high structural strength, good stress distribution, and reliable sealing.
Can the bore be customized?
Yes. The dimensional table specifies the bore as “Specified by purchaser.”
Where are Class 900 Welding Neck Flanges used?
They are commonly used in oil and gas, petrochemical, power generation, marine, chemical processing, and other severe-service piping systems.
Can customized flanges be manufactured?
Yes. Customized flange sizes, holes, bores, materials, facings, coatings, and markings can be supplied.
Can inspection certificates be supplied?
Yes. Material certificates, dimensional reports, UT, MT, PMI, hardness testing, and third-party inspection documentation can be supplied when required.
Contact Us
Looking for reliable ASME B16.47 Series A Class 900 Welding Neck Flanges?
Contact our technical team for dimensional confirmation, material selection, customized manufacturing, and quotations.
Shanxi HongKai Forging Co., Ltd.
Address: Cuijiazhuang Industrial Park, Dingxiang County, Shanxi Province, China
Telephone: +86 13716747092
Email: kevin.zhao@hkflange.com
Clear Communication, and Reliable Technical Support