Tube outside diameter
-
DN15 / 21.30 mm
(5)
-
DN20 / 26.90 mm
(5)
-
DN25 / 33.70 mm
(5)
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DN32 / 42.40 mm
(5)
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DN40 / 48.30 mm
(5)
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DN50 / 60.30 mm
(5)
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DN65 / 76.10 mm
(5)
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DN80 / 88.90 mm
(6)
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DN100 / 108.00 mm
(1)
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DN100 / 114.30 mm
(6)
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DN125 / 139.70 mm
(5)
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DN150 / 159.00 mm
(3)
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DN150 / 168.30 mm
(5)
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DN200 / 219.10 mm
(4)
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DN250 / 273.00 mm
(2)
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DN300 / 323.90 mm
(2)
Steel grade
Availability
Stainless steel forged weld neck flange DN50 60,3 mm EN1092-1/11B1 (PN10/16) 1.4541 / 321
- Tube outside diameter (OD): 60.3 mm
- Number of holes: 4
- Weight: 2.73 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10/16
- Steel grade: 1.4541 / 321
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN100 114,3 mm EN1092-1/11B1 (PN10/16) 1.4301 / 1.4307 / 304 / 304L
- Tube outside diameter (OD): 114.3 mm
- Number of holes: 8
- Weight: 4.54 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10/16
- Steel grade: 1.4301 / 1.4307 / 304 / 304L
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN100 114,3 mm EN1092-1/11B1 (PN10/16) 1.4541 / 321
- Tube outside diameter (OD): 114.3 mm
- Number of holes: 8
- Weight: 4.54 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10/16
- Steel grade: 1.4541 / 321
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN100 114,3 mm EN1092-1/11B1 (PN10/16) 1.4571 / 316Ti
- Tube outside diameter (OD): 114.3 mm
- Number of holes: 8
- Weight: 4.54 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10/16
- Steel grade: 1.4571 / 316Ti
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN100 114,3 mm EN1092-1/11B1 (PN10/16/25/40) 1.4541 / 321
- Tube outside diameter (OD): 114.3 mm
- Number of holes: 8
- Weight: 4.54 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10/16/25/40
- Steel grade: 1.4541 / 321
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN100 114,3 mm EN1092-1/11B1 (PN6) 1.4401 / 316 / 1.4404 / 316L
- Tube outside diameter (OD): 114.3 mm
- Number of holes: 4
- Weight: 3.4 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN6
- Steel grade: 1.4401 / 316 / 1.4404 / 316L
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN125 139,7 mm EN1092-1/11B1 (PN10/16) 1.4301 / 1.4307 / 304 / 304L
- Tube outside diameter (OD): 139.7 mm
- Number of holes: 8
- Weight: 5.9 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10/16
- Steel grade: 1.4301 / 1.4307 / 304 / 304L
Availability:
sold out
Stainless steel forged weld neck flange DN125 139,7 mm EN1092-1/11B1 (PN10/16) 1.4401 / 316 / 1.4404 / 316L
- Tube outside diameter (OD): 139.7 mm
- Number of holes: 8
- Weight: 5.9 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10/16
- Steel grade: 1.4401 / 316 / 1.4404 / 316L
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN125 139,7 mm EN1092-1/11B1 (PN10/16) 1.4541 / 321
- Tube outside diameter (OD): 139.7 mm
- Number of holes: 8
- Weight: 5.9 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10/16
- Steel grade: 1.4541 / 321
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN125 139,7 mm EN1092-1/11B1 (PN10/16) 1.4571 / 316Ti
- Tube outside diameter (OD): 139.7 mm
- Number of holes: 8
- Weight: 5.7 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10/16
- Steel grade: 1.4571 / 316Ti
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN125 139,7 mm EN1092-1/11B1 (PN6) 1.4401 / 316 / 1.4404 / 316L
- Tube outside diameter (OD): 139.7 mm
- Number of holes: 8
- Weight: 4.7 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN6
- Steel grade: 1.4401 / 316 / 1.4404 / 316L
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN15 21,3 mm EN1092-1/11B1 (PN10/16/25/40) 1.4541 / 321
- Tube outside diameter (OD): 21.3 mm
- Number of holes: 4
- Weight: 0.65 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10/16/25/40
- Steel grade: 1.4541 / 321
Availability:
available
Dispatched within: 3 days
Weld neck flanges
Weld neck flanges are a type of butt-weld pipe fitting designed with a tapered hub that is welded to the pipe. The taper helps transfer stress from the flange to the pipe, making these flanges ideal for high-pressure and high-temperature systems. You will also see them called long weld neck flanges, weld-on flanges or butt-weld flanges — names that are often used interchangeably depending on the application.
What is a weld neck flange and where is it used?
A weld neck flange has a raised, tapered hub that is butt-welded to the pipe, producing a smooth bore transition and strong joint. This construction reduces stress concentrations at the connection and is commonly specified where strength and leak-resistance are important. Typical uses include:
- High-pressure and high-temperature piping
- Petrochemical and chemical process plants
- Offshore and marine installations
- Power generation (steam, nuclear and thermal)
- Pharmaceutical and food processing (where hygienic stainless grades are required)
- Water treatment, desalination and HVAC systems
- Automotive, construction and even garage-scale projects that need durable pipe fittings
Long weld neck flanges — when to choose them
Long weld neck flanges are similar to standard weld necks but have an extended hub. The longer neck spreads stresses over a greater length of pipe and is often used in:
- Cryogenic or very high-temperature services
- Pipelines where vibration or cyclic loading is significant
- Situations requiring greater radial reinforcement or easier access for radiographic inspection of the weld
Materials and grades — what we supply
Our online shop specialises exclusively in stainless and heat/acid-resistant stainless steels — we do not supply aluminium or plain carbon steels. Common materials for weld neck flanges include:
- Austenitic stainless steels such as 304 (EN 1.4301 / AISI 304) — general-purpose stainless steel with good corrosion resistance
- Marine and acid-resistant stainless such as 316 and 316L (EN 1.4401 / 1.4404 / AISI 316 / 316L) — better corrosion resistance, commonly used offshore and in chemical environments
- Duplex stainless (e.g. 2205, EN 1.4462 / UNS S32205) — higher strength and improved resistance to chloride stress corrosion cracking
- Heat-resistant grades (commonly used options include AISI 309/310) for elevated temperature services
We use both everyday terms (stainless steel, acid‑resistant steel, heat‑resistant steel) and technical designations (EN numbers and AISI/UNS or common trade names) so you can match material to your specification or engineering drawings.
Standards, pressure ratings and face types
Weld neck flanges are produced to common industry standards such as EN (e.g. EN 1092‑1) and ASME/ANSI (e.g. ASME B16.5/B16.47) depending on size and rating. They are available with different flange faces — raised face (RF) and ring-type joint (RTJ) are the most common — so be sure to match the face type and pressure class to your mating flange and gasket.
Selection and installation tips
- Match material to service: choose 316/316L or duplex for seawater and aggressive chemicals; choose heat-resistant grades for high-temperature systems.
- Size and schedule: ensure the flange bore and hub are compatible with the pipe schedule and inside diameter for a smooth flow path.
- Pressure rating: select the correct pressure class (PN or ANSI class) for your operating conditions.
- Welding: weld neck flanges require butt welding by a qualified welder. Pre‑weld preparation, appropriate filler metal and, where required, post‑weld heat treatment or stress relief and NDT (e.g. radiography) should follow your project’s welding procedure.
- Inspection: verify material certificates (e.g. EN 10204 3.1) and check dimensions to ensure compatibility with existing pipework and fittings.
Who buys weld neck flanges?
Our customers range from small fabrication shops and garage engineers to large contractors and OEMs in industries such as oil & gas, petrochemical, offshore, shipbuilding, power generation, food and pharmaceutical processing, water and wastewater treatment and general construction. Weld neck flanges are chosen whenever long‑lasting, high‑integrity connections and reliable performance are required.
Need help choosing the right weld neck flange?
If you are unsure whether to use a standard weld neck or a long weld neck, which material grade will suit your environment, or how to match flange standards and face types, contact our technical sales team. We can advise on stainless steel grades, pipe fittings compatibility, welding considerations and the correct specification for your application.