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ANSI B16.5 FORGING FLANGE -- Class 600 Long Weld Neck Flange
Long welding neck flange (LWN) is also known as straight hub welding flange. The LWN flange is constructed in two sections: the upper section is a heavy-wall barrel, while the lower section is a disc-like plate flange with all dimensions conforming to ASME B16.5 standard flanges.
According to ASME B16.5, The long welding neck flange is mainly applied to the construction of pressure vessel functioning as a nozzle (such as a thermowell nozzle). To attach a common welding neck flange to a pressure vessel, a piece of pipe is required with additional welding. A LWN flange on the other hand attaches directly to the vessel, hence, it can be viewed as an integrally reinforced nozzle. It avoids making a weld seam at pipe to flange and provides self-reinforcement.
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| Nominal Pipe Size | Outside Diameter | O.D. of Raised Face | Hub Diameter at Bevel | Diameter of Bore | Thickness of Flange Min. | Length Through Hub | DRILLING | ||
| Diameter of Bolt Circle | Number of Holes | Diameter of Holes | |||||||
| D | E | G | B | t | L | C | d | ||
| 1 | 124 | 53.8 | 50.8 | 25.4 | 17.5 | 228.6 | 88.9 | 4 | 19.1 |
| 1 1/4 | 133 | 63.5 | 63.5 | 31.8 | 20.6 | 228.6 | 98.6 | 4 | 19.1 |
| 1 1/2 | 155 | 69.9 | 73.2 | 38.1 | 22.4 | 228.6 | 114.3 | 4 | 22.4 |
| 2 | 165 | 84.1 | 91.9 | 50.8 | 25.4 | 228.6 | 127.0 | 8 | 19.1 |
| 2 1/2 | 191 | 100.1 | 104.6 | 63.5 | 28.4 | 228.6 | 149.4 | 8 | 22.4 |
| 3 | 210 | 117.3 | 127.0 | 76.2 | 31.8 | 228.6 | 168.1 | 8 | 22.4 |
| 3 1/2 | 229 | 133.4 | 139.7 | 88.9 | 35.1 | 228.6 | 184.2 | 8 | 25.4 |
| 4 | 273 | 152.4 | 157.2 | 101.6 | 38.1 | 304.8 | 215.9 | 8 | 25.4 |
| 5 | 330 | 190.5 | 185.7 | 127.0 | 44.5 | 304.8 | 266.7 | 8 | 28.4 |
| 6 | 356 | 222.3 | 215.9 | 152.4 | 47.8 | 304.8 | 292.1 | 12 | 28.4 |
| 8 | 419 | 273.1 | 269.7 | 203.2 | 55.6 | 304.8 | 349.3 | 12 | 31.8 |
| 10 | 508 | 342.9 | 323.9 | 254.0 | 63.5 | 304.8 | 431.8 | 16 | 35.1 |
| 12 | 559 | 400.1 | 381.0 | 304.8 | 66.5 | 304.8 | 489.0 | 20 | 35.1 |
| 14 | 603 | 431.8 | 412.8 | 355.6 | 69.9 | 304.8 | 527.1 | 20 | 38.1 |
| 16 | 686 | 495.3 | 469.9 | 406.4 | 76.2 | 304.8 | 603.3 | 20 | 41.1 |
| 18 | 743 | 546.1 | 533.4 | 457.2 | 82.6 | 304.8 | 654.1 | 20 | 44.5 |
| 20 | 813 | 609.6 | 584.2 | 508.0 | 88.9 | 304.8 | 723.9 | 24 | 44.5 |
| 24 | 940 | 717.6 | 692.2 | 609.6 | 101.6 | 304.8 | 838.2 | 24 | 50.8 |
Notes:
(1) Bore(B) is not the same as the nominal pipe size.
(2) Welding necks longer than listed are available in all sizes on special order.
ANSI B16.5 FORGED FLANGES TOLERANCE
| THREAD,SOCKET-WELDING, SLIP-ON,LAP JOINT AND BLIND. | WELDING NECK | ||||
| Outside Diameter | When O.D.is 24"or less | ±1/16"(1.6mm) | Outside Diameter | When O.D.is 24"or less | ±1/16"(1.6mm)* |
| When O.D.is Over 24" | ±1/8"(3.2mm)* | When O.D.is Over 24" | ±18"(3.2mm) | ||
| Inside Diameter | Threaded | Within limits on boring gauge | Inside Diameter | 10"and Smaller | ±1/32"(0.8mm) |
| 20"thru 18" | ±1/16"(1.6mm) | ||||
| Socket-Welding Slip-on and Lap joint | 10"&Smaller +1/32"(0.8mm).0" 12"&Larger +1/16"(1.6mm).O" | 20"and Larger | +1/8"(3.2mm) -1/16"(1.6mm) | ||
| Outside Diameter of Hub | 5"and Smaller | +3/32"(2.4mm) -1/32"(0.8mm) | Diameter of Hub at Base | When Hub Base is 24"or Smaller | ±1/16"(1.6mm)* |
| 6"and Larger | +5/32"(4.0mm) -1/32"(0.8mm) | When Hub Base is Over 24" | ±1/8"(3.2mm)* | ||
| Diameter of Contact Face | 1/16"Raised Face | ±1/32"(0.8mm) | Diameter of Contact Face | 116"Raised Face | ±1/32"(0.8mm) |
| 1/4"Raised Face Tongue & Groove Male,Female | ±1/64"(0.4mm) | 14"Raised Face Tongue &Groove Male,Female | ±1/64"(0.4mm) | ||
| Diameter of Counterbore | Same as for Inside Diameter | Diameter of Hub at Point of Welding | 5"and Smaller | +3/32"(2.4mm)* -1/32"(0.8mm) | |
| 6"and Larger | +5/32"(4.0mm) -1/32"(0.8mm) | ||||
| Drilling | Bolt Circle | ±1/16"(1.6mm) | Drilling | Bolt Circle | ±1/16"(1.6mm) |
| Bolt Hole Spacing | ±1/32"(0.8mm) | Bolt Hole Spacing | ±1/32"(0.8mm) | ||
| Eccentricity of Bolt Circle with Respect to Facing | 21/2"Smaller 1/32"(0.8mm)Max. 3"&Larger 1/16"(1.6mm)Max | Eccentricity of Bolt Circle with Respect to Facing | 21/2"Smaller 1/32"(0.8mm)Max. 3"&Larger 1/16"(1.6mm)Max. | ||
| Eccentricity of Bolt Circle with Respect to Bore | 1/32"(0.8mm)Max.* | Eccentricity of Bolt Circle with Respect to Bore | 1/32"(0.8mm)Max.* | ||
| Eccentricity of Facing with Respect to Bore | 1/32"(0.8mm)Max.* | Eccentricity of Facing with Respect to Bore | 1/32"(0.8mm)Max.* | ||
| Thickness | 18"and Smaller | +1/8"(3.2mm).0^ | Thickness | 18"and Smaller | +1/8"(3.2mm),0" |
| 20"and Larger | +3/16"(4.8mm).04 | 20"and Larger | +3/16"(4.8mm).O | ||
| Length Thru Hub | 10"and Smaller | ±1/16"(1.6mm) | Length Thru Hub | 10"and Smaller | ±1/16"(1.6mm) |
| 12"and Larger | ±1/8"(3.2mm) | 12"and Larger | ±1/8"(3.2mm) | ||
This tolerance is not covered in ANSI B16.5, but maker's option.
STANDARD FINISHES for Face of Flange (ANSI B16.5)
STOCK FINISH:The most widely used gasket finish.because practically is suitable for all ordinary service conditions. This is a continuous spiral groove. Flanges size 12" (304.8mm)and smaller are produced with a 1/16" round-nosed tool at a feed of 1/32" per revolution. For sizes 14" (355.6mm)and larger. the finish is made with a 1/8" round-nosed tool at a feed of 3/64" per revolution.
SPIRAL SERRATED OR PHONOGRAPHIC:
This finish is produced by using a 90°round-nosed tool.
CONCENTRIC SERRATED:
This finish is produced by using a 90°round-nosed tool.
SMOOTH FINISH:
The cutting tool employed shall have an approximate 0.06"radius.
The resultant surface finish shall have a 125μ inch to 250μ inch(ANSI B16.5 para 6.4;4.1)
1. RAISED FACE AND LARGE MALE AND FEMALE
A serrated-concentric or serrated-spiral finish with 34 to 64 grooves per inch is used.
The cutting tool employed has an approximate 0.06 in.radius.The resultant surface finish shall have a 125μ inch(3.2m)to 500μ inch(12.5μm) approximate roughness.
2. TONGUE AND GROOVE AND SMALL MALE AND FEMALE
The gasket contact surface does not exceed 125μ in. (3.2μm)roughness
3. RING JOINT
The inside wall surface of the gasket groove does not exceed 63μin.(1.6μm)roughness,
4. BLIND
Blind flanges need not be faced in the center if, when this center part is raised, its diameter is at least 1 in. smaller than the inside diameter of the corresponding pressure class fittings. When the center part is depressed, its diameter is not greater than the inside diameter of the corresponding pressure class fittings. Machining of the depressed center is not required.
The manufacturing process of forged flanges begins with the selection of high-quality steel, which is heated and shaped under high pressure in forging dies to enhance its strength and durability. After forging, the flanges are trimmed, heat-treated to relieve internal stresses, and precisely machined to meet the required dimensions. They undergo rigorous inspection and testing for quality assurance, followed by surface treatments for enhanced corrosion resistance. This process results in flanges that are strong, reliable, and suitable for demanding industrial environments.
Dingxiang Country Gu Cheng Forging Company Ltd. is a leading manufacturer in Dingxiang County, Shanxi Province, known as the "Forging Capital of China." Established with a deep-rooted history in forging, we specialize in producing high-quality flanges and forged components for a wide range of industrial applications. Our extensive product line includes ANSI, DIN, JIS, and EN standard flanges and customized forged parts designed to meet specific customer requirements.
Gu Cheng Forging with over 30 years of experience in producing high-quality forged flanges. Including Weld Neck Flange (WN), Slip-On Flange (SO), Blind Flange (BL), Socket Weld Flange (SW), Lap Joint Flange, Plate Flange, and Customized forged flange.
At Gu Cheng Forging, we serve a global market, providing flanges and forged components for industries such as oil and gas, chemical processing, power generation, shipbuilding, and more. We pride ourselves on our ability to deliver tailored solutions, meeting the highest standard of safety, performance, and efficiency.
As a factory, we can tailor flanges based on your specific requirements for size, material, pressure rating, and surface treatment (galvanization, black paint, etc.). By preventing rust and deterioration, the coating enhances the flange's performance, offering long-term resilience and reducing maintenance needs over time.
Dingxiang Country Gu Cheng Forging Company Ltd, strives to be a trusted partner for all your forging needs, ensuring long-term cooperation and mutual success.
Q1: Are you a manufacturer or a trading company?
A1: We are a professional manufacturer with over 30 years of experience in forging flanges. Our factory is located in Dingxiang, China, known as the "Forging Capital." We produce high-quality, customized forged flanges, offering factory-direct pricing and ensuring top-notch quality.
Q2: What types of flanges do you produce?
A2: We manufacture a wide range of forged flanges, including:
- Weld Neck Flange (WN)
- Slip-On Flange (SO)
- Blind Flange (BL)
- Socket Weld Flange (SW)
- Threaded Flange (TH)
- Lap Joint Flange
- Plate Flange
Q3: What materials do you use?
A3: We offer flanges in a variety of materials, including:
- Carbon Steel
- Stainless Steel
- Alloy Steel
Each material is sourced from certified suppliers, ensuring durability and performance in diverse industrial applications.
Q4: Can you provide customized flanges?
A4: Absolutely! As a factory, we specialize in customization. We can tailor flanges based on your specific requirements for size, material, pressure rating, and surface treatment (galvanization, black paint, etc.).
Q5: How do you ensure the quality of your products?
A5: Quality is our top priority. Every flange undergoes a strict inspection process, including:
- Material analysis
- Dimensional checks
- Pressure testing
- Surface treatment inspections
Our CNC machining ensures precise dimensions, and we adhere to strict international standards throughout the manufacturing process.
