Tube outside diameter
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DN15 / 21.30 mm
(1)
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DN20 / 26.90 mm
(1)
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DN25 / 33.70 mm
(1)
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DN32 / 42.40 mm
(1)
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DN40 / 48.30 mm
(1)
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DN50 / 60.30 mm
(1)
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DN65 / 76.10 mm
(1)
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DN80 / 88.90 mm
(1)
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DN100 / 114.30 mm
(2)
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DN125 / 139.70 mm
(1)
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DN150 / 159.00 mm
(1)
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DN150 / 168.30 mm
(1)
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DN200 / 219.10 mm
(2)
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DN250 / 273.00 mm
(1)
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DN300 / 323.90 mm
(1)
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) 1.4541 / 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 (PN10/16/25/40) 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 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 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
Stainless steel forged weld neck flange DN150 159 mm EN1092-1/11B1 (PN10/16) 1.4541 / 321
- Tube outside diameter (OD): 159 mm
- Number of holes: 8
- Weight: 7.75 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 DN20 26,9 mm EN1092-1/11B1 (PN10/16/25/40) 1.4541 / 321
- Tube outside diameter (OD): 26.9 mm
- Number of holes: 4
- Weight: 0.95 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 DN200 219,1 mm EN1092-1/11B1 (PN10) 1.4541 / 321
- Tube outside diameter (OD): 219.1 mm
- Number of holes: 12
- Weight: 11.0 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10
- Steel grade: 1.4541 / 321
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN200 219,1 mm EN1092-1/11B1 (PN10/16) 1.4541 / 321
- Tube outside diameter (OD): 219.1 mm
- Number of holes: 12
- Weight: 11.0 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 DN300 323,9 mm EN1092-1/11B1 (PN10) 1.4541 / 321
- Tube outside diameter (OD): 323.9 mm
- Number of holes: 12
- Weight: 9.73 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10
- Steel grade: 1.4541 / 321
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN32 42,4 mm EN1092-1/11B1 (PN10/16/25/40) 1.4541 / 321
- Tube outside diameter (OD): 42.4 mm
- Number of holes: 4
- Weight: 1.65 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 DN40 48,3 mm EN1092-1/11B1 (PN10/16/25/40) 1.4541 / 321
- Tube outside diameter (OD): 48.3 mm
- Number of holes: 4
- Weight: 1.8 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10/16/25/40
- Steel grade: 1.4541 / 321
Availability:
available
Dispatched within: 3 days
Stainless steel weld neck flanges 1.4541 / 321 — overview
Stainless steel weld neck flanges 1.4541 / 321 are flanged pipe fittings manufactured from the stabilised austenitic stainless steel grade commonly known as 1.4541 (EN), also sold as 321 (AISI/UNS S32100). A weld neck (WN) flange has a long, tapered hub that is butt‑welded to the pipe. That design gives a smooth transition from flange to pipe and is particularly suitable for high‑stress, high‑temperature and high‑pressure applications.
What is a weld neck flange and how is it used?
A weld neck flange is welded to the pipe by its neck, so the internal bore of the flange matches the pipe bore and there is a continuous flow path. This reduces stress concentrations and improves fatigue resistance compared with other flange types. Weld neck flanges are typically used where secure, leak‑resistant connections are required and where the joint must withstand mechanical or thermal stress (for example, steam lines, process piping and high‑pressure services).
Material: 1.4541 / 321 — what that means
Grade 1.4541 (EN) corresponds to AISI 321 (UNS S32100). It is an austenitic stainless steel stabilised with titanium. In practical terms this means:
- Good general corrosion resistance typical of austenitic stainless steels.
- Improved resistance to intergranular corrosion (sensitisation) during welding because of titanium stabilisation — useful for welded flanges.
- Better performance than un‑stabilised grades when exposed to elevated temperatures, so it is often selected for heat‑exposed components such as exhaust systems, heat exchangers and high‑temperature piping.
Common synonyms and designations you may see: 1.4541, 321, AISI 321, UNS S32100.
Typical industries and applications
Stainless steel weld neck flanges 1.4541 / 321 are used across many sectors. Examples include:
- Oil & gas and petrochemical — process piping, high‑temperature lines, and onshore/offshore installations.
- Power generation — steam and boilerpipe connections, heat exchangers.
- Chemical industry — corrosive and high‑temperature process lines.
- Marine and offshore — pipe systems where welding quality and corrosion resistance are critical.
- Automotive and motorsport — exhaust systems and high‑temperature components.
- Light engineering, workshops and garage projects — where a robust, welded flange is preferred for strength and alignment.
- Food & beverage and pharmaceutical — used where higher temperature resistance is needed, although other grades (e.g. 304/316) are commonly used for general food contact.
Standards, faces and configuration options
Weld neck flanges are manufactured to widely recognised standards to ensure interchangeability. Typical standards and options include:
- Standards: EN 1092‑1 (PN flanges) and ASME B16.5 / B16.47 (class/ANSI flanges) are commonly used references for dimensions and drillings.
- Face types: Raised face (RF), flat face (FF) and ring‑type joint (RTJ) are common face options for weld neck flanges.
- Drilling: Drilled to match the bolt pattern required by the chosen standard (DN/PN or ASME class).
- Certifications: Material test certificates (for example EN 10204 3.1) and inspection on request — always specify required certification at order stage.
Advantages of choosing 1.4541 / 321 weld neck flanges
- Weldable and robust: the neck design gives excellent mechanical support and distributes stress into the pipe.
- Weld‑friendly material: titanium stabilisation reduces the risk of intergranular corrosion at welds compared with unstabilised grades.
- High‑temperature suitability: chosen where elevated temperature performance is needed in addition to corrosion resistance.
Who should consider these flanges?
Typical customers include pipefitters, mechanical and plant engineers, fabricators, procurement teams in offshore/petrochemical/power companies, HVAC contractors, vehicle exhaust manufacturers and hobbyists working on high‑temperature projects. If you need a flange that will be welded directly to piping and must withstand mechanical or thermal stress, weld neck flanges in 1.4541 / 321 are a strong option.
Ordering and specification tips
To ensure you receive the correct weld neck flange, be prepared to specify:
- Material grade (e.g. 1.4541 / AISI 321)
- Flange standard and drilling (EN 1092‑1 PN, ASME B16.5 class or other)
- Pipe size (DN or nominal pipe size) and wall thickness / schedule
- Face type (RF, FF, RTJ)
- Surface finish or additional machining requirements
- Required documentation or certification (material test certificates, NDT, etc.)
If you are unsure, contact our technical sales team with the operating pressure, temperature range and the fluid handled — that information allows us to recommend the correct flange standard and face type.
Note on our product range
We supply components only in stainless, acid‑resistant and heat‑resistant steels — we do not stock aluminium or plain carbon steel flanges. If you need alternative stainless grades (for example 304 / 1.4301, 316 / 1.4401) or bespoke machining and certification, please enquire and we will advise available options for your project.