Weld Neck Flange

Arc Alloys Ltd can supply weld neck flanges in a wide variety of material grades, specifications and sizes. Typically they are supplied with a flat face, raised face or RTJ facing so if you are looking for high quality weld neck flanges then please get in touch.

All weld neck flanges can be supplied with grooves, back faces, bevels and bores inlaid with a variety of alloys. This is carried out to stringent industry standards by highly qualified welders and full certification is available.

Size range

  • 3/8” – 60”

Dimensional standards:

  • ANSI B16.5
  • 47 Series A and B16.47 Series B
  • API 6A
  • API 17D
  • BS EN 1092-1
  • BS 4504
  • BS 10
  • Din
  • JIS
  • Norsok L-005
  • Bespoke to customer drawings / design.

Standard grades:

  • ASTM / ASME A182 / SA182 F51 / F60 / 31803/ 1.4462
  • ASTM / ASME  A182 / SA182 F53/F55 / 32750 / 32760
  • ASTM  / ASME A182 / SA182  F44 / 31254
  • ASTM / ASME / B564 / SB564 UNS NO6625 / Alloy 625 / Inconel® 625
  • ASTM / ASME / B564 / SB564 UNS NO8800 / Alloy 800 / Incoloy® 800
  • ASTM / ASME / B564 / SB564 UNS NO8810 / Alloy 800H / Incoloy® 800H
  • ASTM / ASME / B564 / SB564 UNS NO8811 / Alloy 800HT / Incoloy® 800HT
  • ASTM / ASME / B564 / SB564 UNS NO6600 / Alloy 600 / Inconel® 600
  • ASTM / ASME / B564 / SB564 UNS NO6601 / Alloy 601 / Inconel® 601
  • ASTM / ASME / B564 / SB564 UNS NO8020 / Alloy 20 / Carpenter® 20
  • ASTM / ASME / B564 / SB564 UNS NO2200 / Alloy 200
  • ASTM / ASME / B564 / SB564 UNS NO2201 / Alloy 201
  • ASTM / ASME / B564 / SB564 UNS NO6625 / Alloy 400 / Monel® 400
  • ASTM / ASME / B564 / SB564 UNS NO7718 / Alloy 718
  • ASTM / ASME / B564 / SB564 UNS NO8825 / Alloy 825 / Incoloy® 825
  • ASTM / ASME / B564 / SB564 UNS NO10276 / Alloy C276 / Hastelloy®C276
  • ASTM / ASME / B564 / SB564 UNS NO6022 / Alloy 22 / Hastelloy® 22
  • ASTM / ASME / B564 / SB564 UNS NO10675 / Alloy B3 / Hastelloy® B3
  • ASTM / ASME / A182 / SA182 UNS NO8028 / Alloy 28 / Sanicro®28
  • ASTM / ASME / B564 / SB564 UNS NO5500 / Alloy K500 / Monel® K500
  • ASTM / ASME / A182 / SA182 F304 / F304L / F304H
  • ASTM / ASME / A182 / SA182 F316 / F316L / F316H
  • ASTM / ASME / A182 / SA182 F321 / F321H

Standard facings:

  • Raised face
  • Ring-type joint
  • Flat face
  • Male/female
  • Tongue/groove

Arc Alloys Ltd are leading manufacturers and suppliers of weld neck flanges for a variety of industries including oil and gas, refrigeration, refining, filtration, petrochemical and the offshore industry.

Weld neck flanges are used extensively in high pressure systems and they are suitable for both cold and hot temperatures which is an ideal feature for the industries mentioned above.

Weld neck pipe flanges can be attached to a pipe by welding the pipe to the neck of the pipe flange. This transfers the stress from the weld neck flange to the pipe and also reduces the high levels of stress which tend to be concentrated at the base of the weld neck flange.

Weld neck flanges are perfect for high pressure applications and one of the main benefits of using them is that they do not interfere with the flow of liquid through the flange. If you place the weld joint at the neck of the flange, the pipe is easy to align and you can achieve a stronger weld. The neck of the flange is perfectly bevelled and helps the welder to identify the type of bevel that they must place on the pipe before connecting it to the flange.

Features of Weld Neck Flanges

Weld Neck Flanges feature a long tapered hub that goes gradually over to the wall thickness from a pipe or fitting. This provides critical reinforcement for high pressure, high temperature and sub-zero applications.

The tapered hub is created by a gradual increase in thickness of the metal from the weld joint to the flange face. This makes it perfect for conditions of repeated bending caused by line expansion, contraction, or other external forces.

These flanges are carefully bored to perfectly match the inside diameter of the adjoining pipe so there will be no restriction in flow. This helps to prevent turbulence at the joint and ultimately reduces erosion.

Benefits of Weld Neck Flanges

This is a summary of the main benefits:

  • Suitable for high pressure systems and can cope with high and low temperatures.
  • The weld connection does not interfere with flow of the fluid and reduces turbulence.
  • Enables easier alignment between the pipe and flange.
  • Facilitates easy access for radiography testing to check the integrity of welding.
  • All the internal stress is transferred to the pipe through the neck making the connection stronger and longer lasting.
  • The flange face is kept away from heat affected area.