ASME B16.47 Series B Class 150 Welding Neck Flanges are manufactured for large-diameter piping systems according to ASME B16.47 Series B dimensional requirements.
A Welding Neck Flange has a tapered hub and is butt welded directly to the pipe. The gradual transition between the flange hub and pipe helps reduce localized stress and improves connection stability.
The source site describes Weld Neck Flanges as high-neck flanges with extra strength and stability, suitable for industrial systems involving pressure and temperature.
| Parameter | Description |
|---|---|
| Product Name | ASME B16.47 Series B Class 150 Welding Neck Flange |
| Standard | ASME B16.47 Series B |
| Pressure Rating | Class 150 |
| Size Range | NPS 26" – NPS 60" |
| 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 |
| 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) | Maximum Thickness (T) | Length Thru Hub (Y) | Approx. Weight (lbs) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 26 | 30.94 | 29.31 | 28.00 | 36 | 0.88 | Specified by purchaser | 26.06 | 26.94 | 0.38 | 1.62 | 3.50 | 120 |
| 28 | 32.94 | 31.31 | 30.00 | 40 | 0.88 | Specified by purchaser | 28.06 | 28.94 | 0.38 | 1.75 | 3.75 | 140 |
| 30 | 34.94 | 33.31 | 32.00 | 44 | 0.88 | Specified by purchaser | 30.06 | 31.00 | 0.38 | 1.75 | 3.94 | 150 |
| 32 | 37.06 | 35.44 | 34.00 | 48 | 0.88 | Specified by purchaser | 32.06 | 33.06 | 0.38 | 1.81 | 4.25 | 170 |
| 34 | 39.56 | 37.69 | 36.25 | 40 | 1.00 | Specified by purchaser | 34.06 | 35.12 | 0.38 | 1.94 | 4.34 | 210 |
| 36 | 41.62 | 39.75 | 38.25 | 44 | 1.00 | Specified by purchaser | 36.06 | 37.19 | 0.38 | 2.06 | 4.62 | 240 |
| 38 | 44.25 | 42.12 | 40.25 | 40 | 1.12 | Specified by purchaser | 38.12 | 39.25 | 0.38 | 2.12 | 4.88 | 290 |
| 40 | 46.25 | 44.12 | 42.50 | 44 | 1.12 | Specified by purchaser | 40.12 | 41.31 | 0.38 | 2.19 | 5.06 | 310 |
| 42 | 48.25 | 46.12 | 44.50 | 48 | 1.12 | Specified by purchaser | 42.12 | 43.38 | 0.44 | 2.31 | 5.25 | 345 |
| 44 | 50.25 | 48.12 | 46.50 | 52 | 1.12 | Specified by purchaser | 44.12 | 45.38 | 0.44 | 2.38 | 5.38 | 370 |
| 46 | 52.81 | 50.56 | 48.62 | 40 | 1.25 | Specified by purchaser | 46.12 | 47.44 | 0.44 | 2.44 | 5.69 | 435 |
| 48 | 54.81 | 52.56 | 50.75 | 44 | 1.25 | Specified by purchaser | 48.12 | 49.50 | 0.44 | 2.56 | 5.88 | 480 |
| 50 | 56.81 | 54.56 | 52.75 | 48 | 1.25 | Specified by purchaser | 50.12 | 51.50 | 0.44 | 2.69 | 6.06 | 520 |
| 52 | 58.81 | 56.56 | 54.75 | 52 | 1.25 | Specified by purchaser | 52.12 | 53.56 | 0.44 | 2.75 | 6.19 | 550 |
| 54 | 61.00 | 58.75 | 56.75 | 56 | 1.25 | Specified by purchaser | 54.12 | 55.62 | 0.44 | 2.81 | 6.38 | 620 |
| 56 | 63.00 | 60.75 | 58.75 | 60 | 1.25 | Specified by purchaser | 56.12 | 57.69 | 0.56 | 2.88 | 6.56 | 650 |
| 58 | 65.94 | 63.44 | 60.75 | 48 | 1.38 | Specified by purchaser | 58.12 | 59.69 | 0.56 | 2.94 | 6.88 | 780 |
| 60 | 67.94 | 65.44 | 63.00 | 52 | 1.38 | Specified by purchaser | 60.12 | 61.81 | 0.56 | 3.00 | 7.06 | 850 |
Notes:
All dimensions are in inches.
These flanges are furnished with a 1/16" Raised Face unless otherwise specified.
Standard Bore will be furnished unless otherwise specified.
Bore can also be specified by the purchaser according to project requirements.

A Welding Neck Flange has a tapered hub and is connected to the pipe by butt welding.
The hub creates a gradual transition between the flange and pipe, helping improve stress distribution and structural stability.
This type of flange is suitable for:
Large-diameter pipelines
Oil transportation systems
Chemical process pipelines
Ship piping systems
Industrial process piping
Systems exposed to pressure and temperature variation
The source site describes Weld Neck Flanges as suitable for oil transportation pipelines, ship pipeline systems, and chemical raw-material transport.
| 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 |
| 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 |
The butt-welded design provides a stable connection between the pipe and flange.
The tapered hub helps reduce stress concentration around the welded area.
Precision-machined flange faces provide stable gasket contact.
Series B Class 150 Welding Neck Flanges are designed for large-diameter industrial piping systems.
Carbon steel, stainless steel, alloy steel, and duplex stainless steel are available.

Used in large-diameter oil and gas pipelines, processing facilities, and equipment connections.
Suitable for process piping, tanks, pressure vessels, pumps, valves, and heat exchangers.
Used for transporting chemicals and industrial process media.
Applied in cooling systems, process piping, and auxiliary pipelines.
Suitable for ship piping systems and marine industrial applications.
Used in machinery, pressure equipment, pumps, valves, and large industrial pipeline networks.

Our ASME B16.47 Series B Class 150 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.
We specialize in forged flange manufacturing for industrial piping systems.
Each flange is inspected before shipment.

Carbon steel, stainless steel, alloy steel, and duplex stainless steel are available.
Customized sizes, bores, facings, coatings, and markings can be supplied.
We supply flange products to customers in different industries and global markets.


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.






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 B Class 150 dimensional requirements.
The reference table covers NPS 26" to NPS 60".
Class 150 is an ASME pressure-temperature class designation. Actual allowable working pressure depends on material, temperature, gasket, bolting, and piping-system design.
Common materials include carbon steel, stainless steel, alloy steel, and duplex stainless steel.
The source states that these flanges are furnished with a 1/16" Raised Face unless otherwise specified.
Its tapered hub and butt-welded connection provide good structural strength, stress distribution, and reliable sealing.
Yes. The source table lists Bore as Specified by purchaser, and also notes that a standard bore is furnished unless otherwise specified.
They are suitable for oil and gas, petrochemical, chemical processing, power generation, marine, and other large-diameter piping systems.
Yes. Customized sizes, bores, holes, facings, materials, coatings, and markings can be supplied.
Yes. Material certificates, dimensional reports, UT, MT, PMI, hardness testing, and third-party inspection documentation can be supplied when required.
Looking for reliable ASME B16.47 Series B Class 150 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