Weld neck flanges are butt welded to pipes. The flange ID matches the wall thickness of the pipe being used. You can also affix the flange with other flanges using bolts. It allows for the smooth affixation process of the flanges. Moreover, the weld neck flanges perform excellently in an environment with extreme temperature and stress. The biggest benefit of such flanges is their resilience and smooth flow.

What are weld neck Flanges?

Designed for butt weld applications where added strength and stability are desired. Insures easy flow of liquid or gas. Welded to the end of the pipe. Pipe is aso beveled with weld prep to ensure full penetration of the weld.

What are applications of Weld Neck Flanges

Wide variety of applications where there is flexibility in the length of a flanged connection and added strength at the connection is desired.
The applications of weld neck flanges:

  • Fabricated Tank Assemblies
  • Oilfield Skid Assembles
  • Fabrications for Chemical and Petroleum Applications
  • Machinery Construction
  • Transmission Pipe Lines
  • Fabricated Valves

Difference Between a Weld Neck Flanges and a Slip on Flange

Slip-on-flange: 

The slip-on flange fits at the end of a pipe. It comprises a circular fitting. The SOF welding happens in the outer part of the pipe to secure it in place. These flanges are easy to incorporate and budget-friendly as compared to other forms of flanges.

But, it is extremely lighter than a weld neck flange. Hence, the SOF flange cannot withstand high pressure, temperature and vibrations.

Weld neck flange: 

A weld neck flange has a longer neck than a slip-on flange. It extends outwards and is easy to secure the end of any pipe. This feature of the weld neck flange makes it stronger than the slip-on flange. Hence, you can use a weld neck flange in extreme pressure or vibration situations. Unlike Slip the flange, the weld neck flange is expensive due to the manufacturing complexity.

Key differences between Slip on flange and weld neck flanges

To know the weld neck flanges dimensions, you should know the dimensions of the:

  • Pipe Size and wall thickness of mating pipe.
  • Design Pressure and Class
  • Gasket Surface Requested
NPS Dia
D
THK

B

Dia

A

Dia

OD

Height

H

Dia

K

Dia

L

1/2 3.5 0.38 1.19 0.84 1.81 2.38 5/8
3/4 3.88 0.44 1.5 1.05 2 2.75 5/8
1 4.25 0.5 1.94 1.32 2.12 3.12 5/8
1.1/4 4.62 0.56 2.31 1.66 2.19 3.5 5/8
1.1/2 5 0.62 2.56 1.9 2.38 3.88 5/8
2 6 0.69 3.06 2.38 2.44 4.75 3/4
2.1/2 7 0.81 3.56 2.88 2.69 5.5 3/4
3 7.5 0.88 4.25 3.5 2.69 6 3/4
3.1/2 8.5 0.88 4.81 4 2.75 7 3/4
4 9 0.88 5.31 4.5 2.94 7.5 3/4
5 10 0.88 6.44 5.56 3.44 8.5 7/8
6 11 0.94 7.56 6.63 3.44 9.5 7/8
8 13.5 1.06 9.69 8.63 3.94 11.75 7/8
10 16 1.12 12 10.75 3.94 14.25 1
12 19 1.19 14.38 12.75 4.44 17 1
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