Long Weld Neck Flanges Features, Benefits And Specifications

By Author: Jeeten Gupta
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What is a Flange?

A flange is a method of connecting pipes, valves, pumps and other equipment to form a piping system. It also provides easy access for cleaning, inspection or modification. Flanges are usually welded or screwed. Flanged joints are made by bolting together two flanges with a gasket between them to provide a seal.

What is a long Weld neck Flange?

Long weld neck flanges (LWN) are similar to weld neck flanges, and are commonly used in high pressure systems as they can deal with both hot and cold temperatures which is ideal for the industries. This Flange is attached to a pipe by welding the pipe to the neck of the pipe flange. This is because, the LWN Flange helps to reduce stress coming from the pipe. Long weld neck flange, comes with the exception that the neck of this flange is extended and acts like a boring extension. Vessels, columns, barrels are the components where the Long Weld Neck Flanges is generally used.

Long weld neck flanges are similar to a standard weld neck flange but the LWN Flange is significantly longer. A, Key Benefit of using LWN Flange is that it is ideal for ...
... high pressure applications and it does not disturb the flow of fluid coming through the flange. For a Stronger weld, the neck of the flange needs to be placed with the weld joint for a proper alignment to the pipe.

Features of Long Weld Neck Flanges

• Long weld neck flanges feature a long-tapered hub that goes over to the wall thickness from a pipe. This hub gives the flange a strong reinforcement which is provided 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 ideal for conditions of repeated bending caused by line expansion, contraction, or other external forces.
• To Prevent Turbulence at the joints and to reduce corrosion, long weld neck flanges is carefully bored to match the inside diameter of the adjoining pipe so there is no restriction in flow.
Benefits of Using Long Weld Neck Flanges
• Can be Perfectly used for high-pressure systems and can deal with high and low temperatures.
• It Provides, no interference with flow of the liquid and reduces turbulence.
• Long Weld Neck Flange is easy to align between the pipe and flange.
• Gives an easy access for radiography testing to check the integrity of welding.
• The internal stress is transferred to the pipe through the neck making the connection stronger and more durable.
• The flange face is kept away from heat affected area

Specification of Long Weld Neck Flange

Standards
ANSI, JIS, DIN, EN1092-1, UNI, BS4504, SABS1123, AS2129, GOST-12820

Dimension
ANSI B 16.5, BS 1560. BS 10, IS 6392, B-2.1 NPT, API, DIN, JIS. MSS SP 44

Material
ASTM A105, ASME A105
ASTM A266 GR.1, GR.2, GR.3, GR.4
ASTM A350 LF1, LF2 CL1/CL2, LF3 CL1/CL2
ASTM A694 F42, F46, F48, F50, F52, F56, F60, F65, F70

Class
150#, 300#, 400 #, 600#, 900#, 1500# and 2500#

Size
1/2” NB TO 24” NB.

Wall Thickness
SCH.10, 20, 30, 40, 80, 120, 160, STD, XS, XXS.

Form
Long weld neck Flanges

More Resources:

• Slip on Flanges Benefits and it uses in the Industries
• A Quick Guide to Weld Neck Flanges
• What are Blind Flange and how it is differs from other type of Flanges?