Tube outside diameter
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DN15 / 21.30 mm
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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
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DN80 / 88.90 mm
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DN100 / 108.00 mm
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DN100 / 114.30 mm
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DN125 / 139.70 mm
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DN150 / 159.00 mm
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DN150 / 168.30 mm
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DN200 / 219.10 mm
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DN300 / 323.90 mm
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Steel grade
Availability
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 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 DN150 159 mm EN1092-1/11B1 (PN10/16) 1.4301 / 1.4307 / 304 / 304L
- Tube outside diameter (OD): 159 mm
- Number of holes: 8
- Weight: 7.36 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 DN150 168,3 mm EN1092-1/11B1 (PN10/16) 1.4301 / 1.4307 / 304 / 304L
- Tube outside diameter (OD): 168.3 mm
- Number of holes: 8
- Weight: 7.36 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 DN20 26,9 mm EN1092-1/11B1 (PN10/16/25/40) 1.4301 / 1.4307 / 304 / 304L
- 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: 1.4301 / 1.4307 / 304 / 304L
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN200 219,1 mm EN1092-1/11B1 (PN10/16) 1.4301 / 1.4307 / 304 / 304L
- 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: 1.4301 / 1.4307 / 304 / 304L
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN25 33,7 mm EN1092-1/11B1 (PN10/16/25/40) 1.4301 / 1.4307 / 304 / 304L
- Tube outside diameter (OD): 33.7 mm
- Number of holes: 4
- Weight: 1.12 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10/16/25/40
- Steel grade: 1.4301 / 1.4307 / 304 / 304L
Availability:
sold out
Stainless steel forged weld neck flange DN300 323,9 mm EN1092-1/11B1 (PN10) 1.4301 / 1.4307 / 304 / 304L
- Tube outside diameter (OD): 323.9 mm
- Number of holes: 12
- Weight: 11.0 kg
- Norm: EN1092-1/11B1
- Nominal pressure: PN10
- Steel grade: 1.4301 / 1.4307 / 304 / 304L
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN32 42,4 mm EN1092-1/11B1 (PN10/16/25/40) 1.4301 / 1.4307 / 304 / 304L
- 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: 1.4301 / 1.4307 / 304 / 304L
Availability:
available
Dispatched within: 3 days
Stainless steel forged weld neck flange DN40 48,3 mm EN1092-1/11B1 (PN10/16/25/40) 1.4301 / 1.4307 / 304 / 304L
- 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: 1.4301 / 1.4307 / 304 / 304L
Availability:
sold out
Stainless steel forged weld neck flange DN65 76,1 mm EN1092-1/11B1 (PN10/16) 1.4301 / 1.4307 / 304 / 304L
- Tube outside diameter (OD): 76.1 mm
- Number of holes: 8
- Weight: 3.06 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 108 mm EN1092-1/11B1 (PN10/16) 1.4301 / 1.4307 / 304 / 304L
- Tube outside diameter (OD): 108 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:
sold out
Stainless steel weld neck flanges 1.4307/304L — product overview
Stainless steel weld neck flanges 1.4307/304L are butt-weld pipe flanges made from the low‑carbon austenitic grade commonly identified as 1.4307 in Europe and 304L (AISI/ASTM) in the United States. These flanges have a long tapered hub that is butt‑welded to a pipe, giving strong connection and good stress distribution at the joint. They are widely used where welding quality, alignment and mechanical strength around the pipe entry are important.
What is 1.4307 / 304L stainless steel?
Grade 1.4307 (304L) is an austenitic stainless steel with reduced carbon content (low carbon, typically max 0.03%) to minimise carbide precipitation during welding. In practice this means better resistance to intergranular corrosion after high‑temperature exposure compared with standard 304 (1.4301). Equivalent designations you may see are AISI/ASTM 304L and UNS S30403.
Typical features and benefits
- Good general corrosion resistance — suitable for water, steam, mild chemicals and many food and beverage applications.
- Excellent weldability — low carbon content reduces risk of sensitisation, making it well suited to welded neck flanges.
- Mechanical strength and alignment — the tapered hub reduces stress concentration at the weld, beneficial for pressure systems.
- Available to common flange standards — these flanges are commonly supplied to standards such as EN 1092‑1 (Europe) and ASME B16.5 / B16.47 (USA), and in a variety of face and bore options (raised face, flat face, ring‑type joint; standard or full bore).
Where weld neck flanges 1.4307/304L are used
Stainless steel weld neck flanges 1.4307/304L are used across a wide range of sectors because of their combination of corrosion resistance and weldability. Typical applications include:
- Process piping in food, beverage and pharmaceutical plants (where hygienic cleaning and corrosion resistance are important).
- Chemical and petrochemical systems handling mild corrosives and process streams.
- HVAC, steam and water systems in commercial and industrial buildings.
- Automotive and manufacturing workshops for exhaust, cooling and laboratory installations.
- Marine and offshore installations for piping where general corrosion resistance is required (for highly chloride‑rich or very aggressive marine environments, higher alloy grades such as 316/1.4401 may be preferred).
- Small‑scale and DIY fabrications or garage projects where stainless pipework and welded joints are needed.
Who buys these flanges
Typical buyers include pipework fabricators, mechanical and project engineers, maintenance and shutdown teams, builders working on commercial installations, shipyards, food and beverage plant engineers, and hobbyists or small workshops undertaking stainless steel fabrications.
How to select and use weld neck flanges
When choosing weld neck flanges (304L), consider:
- Correct standard and pressure rating for your system (e.g. EN or ASME classes).
- Face type (raised face, flat face, RTJ) and whether you need a full bore or reduced bore.
- Pipe material and wall thickness — choose a flange that matches your pipe schedule and welding procedure.
- Environment — for aggressive chloride environments consider upgrading to 316/1.4401/316L where appropriate.
Installation tips: ensure correct butt‑welding technique and pre‑/post weld cleaning to avoid contamination. Use appropriate gaskets and fasteners compatible with stainless steel to maintain corrosion resistance.
Materials we specialise in
Our store focuses exclusively on stainless steels, heat‑resistant and acid‑resistant steels. We do not supply aluminium or plain carbon (non‑stainless) steels. For this category the material is stainless austenitic steel 1.4307 / 304L, commonly referred to in everyday language as stainless steel 304L or simply stainless.
Summary
Stainless steel weld neck flanges 1.4307/304L combine the advantages of a weldable, low‑carbon austenitic grade with the mechanical benefits of the weld neck design. They are a reliable choice for a broad range of piping systems — from small garage fabrications to industrial process, construction, automotive and offshore applications — where weld integrity and corrosion resistance are required. If your application involves aggressive chloride exposure or higher corrosion demands, we can advise on alternative grades such as 316/1.4401/316L.