Skip to content

Understanding the Types and Uses of Weld Neck Flanges

The weld neck flange is a common feature in industrial operations, helping to reduce stress concentrations at the bottom of the flange by distributing stress from the pipes. It comes in two types, one suitable for gaskets and the other longed version suitable for operative industrial plants but not for pipes.

The flange includes a circular component that extends beyond the rim’s circumference, produced by forging and welding to the pipes. The rim has several holes allowing bolted attachment, thus making it more structurally sound.

Uses of Weld Neck Flanges in Various Applications

The weld neck flange is widespread in industrial environments due to its versatility, reliability, and simplicity of installation and replacement. This piece will concentrate on the slip weld neck flanges, disclosing their potential applications in different industries, the welding technique used, and the numerous options provided.

The weld neck flanges are commonly used in pipe fittings to connect pipes. These flanges create a dependable connection between two pipes or tubes and link various valves and parts in a piping system. Slip-weld neck flanges are effective in chemical plants, oil rigs, and water pipelines.

How is Welding Done for Weld Neck Flanges?

To securely attach slip weld neck flanges, two options are available. First, use a welding machine or manually use an oxy-acetylene torch. Careful connecting of all parts is crucial to prevent leakage or gaps. Moreover, it is necessary to utilize the appropriate welding filler material to achieve a robust bond among the merged parts.

What Are the Different Types of Weld Neck Flanges?

Many types of slip-weld neck flanges can be bought from manufacturers. You get choices like the raised face, blind, lap joint, socket weld, and threaded varieties. The most appropriate option for your specific project will be determined by your requirements, along with the flange specifications of your particular application.

Blind Flange

Blind flanges are utilized when the space is limited or restricted for a threaded or lap joint connection. Socket welds have higher pressure ratings as they sink deeper into the end of the pipe. Lap joints are great for situations that require frequent dismantling as they fit loosely.

Threaded connections are effortless to install and remove. Furthermore, raised face slips help prevent leaks by providing a robust seal between two pipes when fastened with bolts or screws.

Long weld neck Flange

The Long Welding Neck Flange is an enlarged version of the commonly used welding neck flange. It is frequently used as a nozzle for columns and barrels and comes in two types: the LWN Heavy Barrel and the Equal LWN Barrel. Both versions have a robust wall structure and unique shapes.

Reducing Weld Neck Flange

A “Reducing Weld Neck Flange” is not a distinct kind of flange. The term “reducing” generally indicates a flange that links pipes or fittings of varying sizes and is made to transform from a bigger pipe size to a smaller one. A “reducing flange” with a larger outer diameter (OD) on one side and a smaller OD on the other is used to connect pipes with different diameters.

Standard Weld Neck Flange

A standard weld neck flange is a flange variety with a lengthy, conical neck that joins pipes via butt weld strengthening the joint and spreading the stress onto the pipe.

NW Long Weld Neck Flanges

The NW LWN flanges, also known as NW Long Weld Neck Flanges, are a flange type frequently used for vacuum systems. These flanges are defined by their elongated, tapering necks and are typically composed of high-quality materials like stainless steel.

Their lengthy neck adds durability and stiffening, making them appropriate for high-vacuum applications. These flanges are designed to be directly welded onto the vacuum chamber or other vacuum system elements to ensure an airtight and secure connection that maintains the vacuum system’s integrity.

The NW Long Weld Neck Flanges follow industry standards, such as DIN 28403 or ISO 2861, and come in different sizes ranging from NW10 to NW50, each with a different outer diameter and bolt-hole pattern.

Materials used in Weld Neck Flanges

Various materials are appropriate for Welding neck flanges, as specified by standards, with the highest level of quality regulated by ASTM and ASME rules. The flange thickness and internal diameter of the flange should match the intended pipe size. Due to its exceptional resistance to extreme temperatures, carbon alloy is a highly desirable material for flange production.

Clients and professionals can benefit from different flange weights and grades, like the ASME B16 47 ‘A’ Series and ‘B’ Series. Additionally, stainless steel welding neck flanges made from ASTM A182, F304, 316L, 347H, 310S, and ASME B16 5 are available and finished with duplex steel.

Several materials are used in creating welding neck flanges, including stainless steel, carbon alloy, nickel alloy, and others, such as UNS S31803 Duplex Steel. Nickel Alloy materials such as Inconel 600 and 625, Hastelloy C22, and C276 are among the many options available.

Weld Neck Flange Dimensions

Various sizes of Class 150 ASME B16.5 weld neck flanges are available, ranging from 1/2″ to 24″. Each size has a different outside and inside diameter, raised face thickness, and several bolt holes. The smallest size has an outer diameter of 3.50″ and four bolt holes, while the largest has an outer diameter of 32.00″ and a raised face thickness of 5.69″.


If you need a dependable method for joining two pipes or linking valves and other parts in your system, slip-weld neck flanges are the answer. They can be of different types, including blind slips for compact areas and raised faces for added leak protection, and they’re affordable and easy to set up.

You can use an automated welding machine or a manual oxy-acetylene torch. However, it will depend on what your requirements are. As long as you maintain and install them, these sturdy components can last many years, even in challenging environments.

If you want the best weld neck flanges, contact Texas Flange today!


0 0 votes
Article Rating
Notify of
Newest Most Voted
Inline Feedbacks
View all comments
29 days ago

The versatility and reliability of slip-weld neck flanges make them a crucial component in various industries. It’s fascinating how they facilitate dependable connections between pipes, enhancing the overall stability of piping systems.

29 days ago

The detailed explanation of different types of weld neck flanges, such as blind, lap joint, socket weld, and threaded varieties, provides valuable insights into choosing the most suitable option based on specific project requirements and applications.

29 days ago

What are the key considerations when choosing the welding technique for slip-weld neck flanges?

24 days ago
Reply to  Selina

Two options are available for securely attaching slip-weld neck flanges: using a welding machine or manually using an oxy-acetylene torch. Careful connection and the use of appropriate welding filler material are crucial to prevent leakage or gaps.

29 days ago

Can you explain the significance of the NW Long Weld Neck Flanges in vacuum systems, and what standards do they follow?

28 days ago
Reply to  Malcolm

NW Long Weld Neck Flanges, designed for high-vacuum applications, have elongated, tapering necks for durability and stiffening. They adhere to industry standards like DIN 28403 or ISO 2861, coming in various sizes (NW10 to NW50) with different outer diameters and bolt-hole patterns.

28 days ago

The focus on materials used in weld neck flanges, including carbon alloy and stainless steel, highlights the importance of choosing the right material for optimal performance, especially considering factors like extreme temperatures and resistance.

Jeff Sterling
Jeff Sterling
3 days ago

Thanks for doing these blogs they are very informative and show up on my google feed.