ASME B16.47 Series B Class 150 Blind Flanges are manufactured for large-diameter piping systems according to ASME B16.47 Series B dimensional requirements.
Unlike Welding Neck Flanges, Blind Flanges have no pipe bore. Their solid circular construction completely closes the pipeline or equipment opening.
The flange is installed against a matching flange using bolts, nuts, and a suitable gasket. This creates a secure but removable closure, making it convenient for system isolation, inspection, maintenance, and pressure testing.
| Parameter | Description |
|---|---|
| Product Name | ASME B16.47 Series B Class 150 Blind Flange |
| Standard | ASME B16.47 Series B |
| Pressure Rating | Class 150 |
| Size Range | NPS 26" – NPS 60" |
| Flange Type | Blind Flange |
| Connection | Bolted Connection |
| 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, Power Generation, Chemical Processing and Industrial Pipelines |
| Nominal Pipe Size | Outside Diameter (O) | Bolt Circle (W) | Raised Face Diameter (R) | Number of Holes | Diameter of Holes | Minimum Thickness (T) | Approximate Weight (lbs) |
|---|---|---|---|---|---|---|---|
| 26 | 30.94 | 29.31 | 28.00 | 36 | 0.88 | 1.75 | 375 |
| 28 | 32.94 | 31.31 | 30.00 | 40 | 0.88 | 1.88 | 455 |
| 30 | 34.94 | 33.31 | 32.00 | 44 | 0.88 | 2.00 | 545 |
| 32 | 37.06 | 35.44 | 34.00 | 48 | 0.88 | 2.12 | 648 |
| 34 | 39.56 | 37.69 | 36.25 | 40 | 1.00 | 2.25 | 782 |
| 36 | 41.62 | 39.75 | 38.25 | 44 | 1.00 | 2.31 | 890 |
| 38 | 44.25 | 42.12 | 40.25 | 40 | 1.12 | 2.50 | 1090 |
| 40 | 46.25 | 44.12 | 42.50 | 44 | 1.12 | 2.62 | 1247 |
| 42 | 48.25 | 46.12 | 44.50 | 48 | 1.12 | 2.69 | 1393 |
| 44 | 50.25 | 48.12 | 46.50 | 52 | 1.12 | 2.81 | 1579 |
| 46 | 52.81 | 50.56 | 48.62 | 40 | 1.25 | 2.94 | 1825 |
| 48 | 54.81 | 52.56 | 50.75 | 44 | 1.25 | 3.06 | 2045 |
| 50 | 56.81 | 54.56 | 52.75 | 48 | 1.25 | 3.18 | 2284 |
| 52 | 58.81 | 56.56 | 54.75 | 52 | 1.25 | 3.31 | 2547 |
| 54 | 61.00 | 58.75 | 56.75 | 56 | 1.25 | 3.44 | 2848 |
| 56 | 63.00 | 60.75 | 58.75 | 60 | 1.25 | 3.56 | 3145 |
| 58 | 65.94 | 63.44 | 60.75 | 48 | 1.38 | 3.68 | 3560 |
| 60 | 67.94 | 65.44 | 63.00 | 52 | 1.38 | 3.81 | 3913 |
Notes:

A Blind Flange is a solid circular flange without a central pipe opening.
Its main purpose is to close the end of a pipeline or equipment connection and provide complete isolation.
Because the flange is bolted rather than permanently welded shut, it can be removed when access is required.
Typical functions include:
| 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 solid flange design provides complete closure for pipeline ends and equipment connections.
The bolted structure allows the flange to be removed when inspection or maintenance is needed.
Precision-machined sealing surfaces provide stable gasket contact.
Series B Class 150 Blind Flanges are suitable for large industrial piping systems from NPS 26" to NPS 60".
Carbon steel, stainless steel, alloy steel, and duplex stainless steel are available.

Used for large-diameter pipeline closure, isolation points, processing facilities, and equipment connections.
Suitable for process piping, tanks, pressure vessels, pumps, valves, and heat exchangers.
Applied in cooling water systems, process piping, and auxiliary pipeline systems.
Used to isolate pipelines carrying chemicals, gases, and industrial process media.
Suitable for large-diameter water systems, utility piping, and general industrial applications.
Used in machinery, pressure equipment, pumps, valves, and large industrial pipeline networks.

Our ASME B16.47 Series B Class 150 Blind Flanges are manufactured through a controlled production process.
Raw Material Inspection → Cutting → Heating → Forging → Heat Treatment → Rough Machining → CNC Machining → Drilling → Sealing Face Machining → Inspection → Surface Treatment → Marking → Packing

Each stage is controlled to ensure accurate dimensions, correct bolt-hole arrangements, stable material properties, 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, 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 Blind Flanges, Welding Neck 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 solid flange without a central pipe opening, designed to close or isolate pipelines and equipment connections.
The reference dimensional 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 overall system design.
Common materials include carbon steel, stainless steel, alloy steel, and duplex stainless steel.
The reference page states that Class 150 Series B Blind Flanges are furnished with a 1/16" Raised Face unless otherwise specified.
It is mainly used for pipeline closure, equipment isolation, pressure testing, maintenance access, and system shutdown.
Yes. The source page states that custom flange types and hole arrangements can be supplied according to customer technical or design needs.
The reference page specifically identifies oil and gas, petrochemical, and power generation applications.
Yes. Material certificates, dimensional inspection 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 Blind 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