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ASME B16.47 Series B Class 75 Welding Neck Flanges
Material: Carbon Steel, Stainless Steel, Alloy Steel, Duplex Stainless Steel
Thickness: According to ASME B16.47 Series B Class 75
Standard: ASME B16.47 Series B
Pressure Class: Class 75
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 B Class 75 Welding Neck Flanges are large-diameter forged flanges designed for industrial piping systems that require reliable sealing, dimensional accuracy, and stable mechanical performance.
The tapered hub and butt-welded connection provide a smooth transition between the flange and pipe, helping distribute stress and improve connection strength.
These flanges are commonly used in oil and gas, petrochemical, power generation, chemical processing, marine, and other large-diameter industrial piping systems. The reference page specifically mentions oil and gas, petrochemical, and power generation applications.
ASME B16.47 Series B Class 75 Welding Neck Flanges Descriptions
ASME B16.47 Series B Class 75 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 connected directly to the pipe by butt welding. This design provides good structural strength and helps reduce stress concentration around the welded joint.
The reference page describes Weld Neck Flanges as high-neck flanges with extra strength and stability, suitable for industrial applications involving temperature and pressure.
Product Parameters
| Parameter | Description |
|---|---|
| Product Name | ASME B16.47 Series B Class 75 Welding Neck Flange |
| Standard | ASME B16.47 Series B |
| Pressure Rating | Class 75 |
| 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 |
ASME B16.47 Series B Class 75 Welding Neck Flange Dimensions
Class 75 Dimensions | ASME B16.47 Series B 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 | 30.00 | 28.50 | 27.75 | 36 | 0.75 | Specified by purchaser | 26.06 | 26.62 | 0.31 | 1.31 | 2.31 | 80 |
| 28 | 32.00 | 30.50 | 29.75 | 40 | 0.75 | Specified by purchaser | 28.06 | 28.62 | 0.31 | 1.31 | 2.44 | 85 |
| 30 | 34.00 | 32.50 | 31.75 | 44 | 0.75 | Specified by purchaser | 30.06 | 30.62 | 0.31 | 1.31 | 2.56 | 90 |
| 32 | 36.00 | 34.50 | 33.75 | 48 | 0.75 | Specified by purchaser | 32.06 | 32.62 | 0.31 | 1.38 | 2.75 | 105 |
| 34 | 38.00 | 36.50 | 35.75 | 52 | 0.75 | Specified by purchaser | 34.06 | 34.62 | 0.31 | 1.38 | 2.88 | 110 |
| 36 | 40.69 | 39.06 | 38.00 | 40 | 0.88 | Specified by purchaser | 36.06 | 36.81 | 0.38 | 1.44 | 3.38 | 145 |
| 38 | 42.69 | 41.06 | 40.00 | 40 | 0.88 | Specified by purchaser | 38.06 | 38.81 | 0.38 | 1.50 | 3.50 | 160 |
| 40 | 44.69 | 43.06 | 42.00 | 44 | 0.88 | Specified by purchaser | 40.06 | 40.81 | 0.38 | 1.50 | 3.62 | 170 |
| 42 | 46.69 | 45.06 | 44.00 | 48 | 0.88 | Specified by purchaser | 42.06 | 42.81 | 0.38 | 1.56 | 3.75 | 185 |
| 44 | 49.25 | 47.38 | 46.25 | 36 | 1.00 | Specified by purchaser | 44.06 | 44.88 | 0.38 | 1.69 | 4.12 | 230 |
| 46 | 51.25 | 49.38 | 48.25 | 40 | 1.00 | Specified by purchaser | 46.06 | 46.88 | 0.38 | 1.75 | 4.25 | 245 |
| 48 | 53.25 | 51.38 | 50.25 | 44 | 1.00 | Specified by purchaser | 48.06 | 48.88 | 0.38 | 1.81 | 4.38 | 270 |
| 50 | 55.25 | 53.38 | 52.25 | 44 | 1.00 | Specified by purchaser | 50.06 | 50.94 | 0.38 | 1.88 | 4.56 | 290 |
| 52 | 57.38 | 55.50 | 54.25 | 48 | 1.00 | Specified by purchaser | 52.06 | 52.94 | 0.38 | 1.88 | 4.75 | 310 |
| 54 | 59.38 | 57.50 | 56.25 | 48 | 1.00 | Specified by purchaser | 54.06 | 55.00 | 0.38 | 1.94 | 4.94 | 340 |
| 56 | 62.00 | 59.88 | 58.50 | 40 | 1.12 | Specified by purchaser | 56.06 | 57.12 | 0.44 | 2.00 | 5.31 | 400 |
| 58 | 64.00 | 61.88 | 60.50 | 44 | 1.12 | Specified by purchaser | 58.06 | 59.12 | 0.44 | 2.06 | 5.44 | 430 |
| 60 | 66.00 | 63.88 | 62.50 | 44 | 1.12 | Specified by purchaser | 60.06 | 61.12 | 0.44 | 2.19 | 5.69 | 475 |
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 dimensions can also be supplied according to purchaser requirements.
Welding Neck Flange
A Welding Neck Flange has a neck and a round tube transition and is attached directly to the pipe.
The tapered hub helps provide extra strength and stability while improving stress distribution around the welded connection.
It is suitable for industrial piping systems involving:
- Oil transportation pipelines
- Ship piping systems
- Chemical raw-material transport
- Large-diameter process pipelines
- Temperature and pressure variations
The reference page highlights structural strength, sealing performance, corrosion resistance, and resistance to high temperature and pressure as key characteristics of Welding Neck Flanges.
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 B Class 75 Welding Neck Flanges
Strong Connection
The butt-welded connection provides a stable pipe-to-flange joint.
Good Stress Distribution
The tapered hub helps reduce stress concentration around the welded area.
Reliable Sealing
Precision-machined sealing surfaces provide stable gasket contact.
Suitable for Large-Diameter Pipelines
Series B Class 75 Welding Neck Flanges are suitable for large industrial piping systems.
Multiple Material Options
Carbon steel, stainless steel, alloy steel, and duplex stainless steel are available.
Applications
Oil and Gas Industry
Used in large-diameter oil and gas pipelines, processing facilities, and equipment connections.
Petrochemical Industry
Suitable for process piping, pressure vessels, tanks, pumps, and valves.
Chemical Processing
Used for chemical raw-material transportation and industrial process pipelines.
Power Generation
Applied in cooling water systems, auxiliary piping, and power-generation facilities.
Marine and Shipbuilding
Suitable for ship piping systems and marine industrial applications.
Industrial Piping
Used in machinery, pressure equipment, valves, pumps, and general large-diameter piping systems.
PRODUCTION PROCESS
Our ASME B16.47 Series B Class 75 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 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 B Class 75 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 B Class 75 dimensional requirements.
What sizes are available?
The reference table covers NPS 26" to NPS 60".
What does Class 75 mean?
Class 75 is an ASME pressure-temperature class designation for Series B flanges. Actual allowable working pressure depends on material, temperature, gasket, bolting, and 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 1/16" Raised Face unless otherwise specified.
Why use a Welding Neck Flange?
Its tapered hub and butt-welded connection provide good mechanical strength, stress distribution, and reliable sealing.
Can the bore be customized?
Yes. The table lists the bore as Specified by purchaser, while the page also notes that a standard bore is furnished unless otherwise specified.
Where are Series B Class 75 Welding Neck Flanges used?
They are commonly used in oil and gas, petrochemical, power generation, chemical processing, marine, and other large-diameter piping systems.
Can customized flanges be manufactured?
Yes. Customized 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 B Class 75 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