5 Important Questions to Ask About Pipe Flange

Most people need to learn what long weld neck flanges are and their use. Some people work in specific industries that encounter the flanges each day. Here you will understand everything you need to know about the basic flanges, including the long weld neck flanges.

Weld-neck flanges


Where do you use flanges the most?

A flange comes disc-shaped, and we use them mostly when building pipelines. According to the Pipeline and Hazardous Materials Safety Administration, 1,382,569 million miles of pipelines deliver oil and gas daily. Long weld necks and other kinds of flanges are a part of pipeline engineering. Flanges are one of the essential parts of pipeline engineering. We use them to connect pipes together and ensure the proper seal.

What is the function of flanges?

Flanges are useful to connect pipes and can also help connect chuck valves, T, and other pipeline parts. Therefore, we consider them a mechanical way to connect pipelines and their parts.

You can weld flanges sometimes, and in other cases, you can hold them together with the fasteners. It all depends on the pipeline engineering and where you can use the flange to determine how well you can connect them.

What are the different flange types?

There are many flanges designed for different purposes. For example, there are high hub flanges, expander flanges, long weld neck flanges, anchor flanges, blind flanges, and more. Within each kind of flange category, there are subcategories.

The metal material may vary, the sizes vary, and how the flange is attached may vary. You can get a lot to learn about the flanges. A proper flange is essential to get off the right seal. A too-large or too-small flange will throw the entire design off.

What is the height of the face in the raised face flange?

The height of the flange face should not be random but, instead, based on the flange ratings. For example, for 300# & 150#, the height of the raised face is 1/16”, which is approximately 1.6 mm, and above 300#, it is 1/4”, which is 6.35 mm.

What is the serration on the flange face, and what type is used on flange faces?

Flange faces could be serrated and smooth type. The flange face with small grooves is known as serration.

The serration is critical as it helps prevent leakages from the flange. Even small damage to the face may lead to the plant shutdown. Thus, if you are working with a flange, ensure to take measures and protect the flange while handling it.

Serration could be concentric or spiral rings. When we talk about concentric ring-type finishing, it is when the fluid used is of very low density. If you use the spiral-type finish with lower-density fluid, it may find a leakage path through the spiral cavity.


The above questions clearly define the pipe flange. The right source, like Texas Flange, will likely offer you a wide variety of high-quality flanges that will fit the project’s needs. Texas Flange will also be able to answer questions and make suggestions to ensure you get the right flange for your project. Call Texas Flange to learn more about our quality flange and how they enhance pipeline projects worldwide.

Variety of Flanges Available at Texas Flange

The type of flange used for a piping application usually depends on the required strength for the flanged joint. Flanges are used to weld connections. In addition, it helps to facilitate maintenance operations.

Let’s dive in to show the key types of flanges with pictures.

Forged Flanges

Welding neck flange

A welding neck flange features a long tapered hub that helps weld the pipe. The flange type is normally used in high/low temperatures and high-pressure applications requiring unrestricted flow if the piping system conveys the fluid.

The absence of pressure drops prevents the adverse effects of erosion/corrosion and turbulence of the metals in the flanged joint proximity.

Long welding neck

Long weld neck flanges are quite similar to weld neck flanges. However, it comes with the exception that the neck is extended and acts like a boring extension.

Long weld neck flanges are usually used on barrels, columns, or vessels.

Slip-on flange

You can connect the slip-on flange to the pipe or the fittings by the two fillet welds, one outside and one executed inside the flange cavity.

The bore size of the slip-on flange is large than the outside diameter for pipe connection, as the pipe has to slide inside the flange that you can connect by the execution of the fillet weld.

Threaded flanges

Threaded flanges are joined to the pipes by screwing the pipe onto the flange without the seam welds. Threaded flanges are available in sizes for up to four inches and multiple pressure ratings; however, they are used mostly in low-temperature applications and small-size piping in low-pressure-like air and water utility services.

Socket weld flange

You can connect socket weld flanges to pipes with the use of a single fillet weld executed on the outer flange side.

As per the ASME B31.1, to execute the flanged connection with a socket weld, the pipe must first insert the flange’s socket until it reaches the bottom of the flange. It then needs to be lifted by 1.6 mm and welded finally.

Lap joint flange

The lap joint flange features a flat face and is always useful in conjunction with the stub end. Lap joint flanges usually resemble the shape of slip-on flanges, except for the radius at the flange face crossing and the bore to accommodate the flanged portion of the stub end.

When we talk about the lap joint flange, it can slip over the pipe and seats on the back of the stub end, and you can keep the two together by the pressure of the bolts.

Blind flanges

Contrary to all the flange types above, blind flanges do not have a center hole. Therefore, you can use the seal or blind in a pipeline or a pressure/valve vessel to block the fluid of the liquid.

Blind flanges need to withstand remarkable mechanical stress due to the system pressure and required bolting forces.

You can easily access the blind flanges to the pipeline, as they can be easily unbolted to let the operator execute the activities while inside the terminal end of the pipe.

Interestingly, while this flange type is easy to manufacture, it is sold at the average premium cost per kg compared to the other flange types.

Special types of flanges

The special types of flanges include:

1. Nipoflange

2. Weldoflange

3. Latroflange or Elboflange

4. Swivel flange

5. Expanding flange

6. Reducing flange


The flanges mentioned above are usually the top flanges available to us. However, you can get in touch with Texas flange if you are looking for top-quality flanges. You can also contact us for any queries regarding the flange function.

How to Use Long Weld Neck Flanges in Industrial Applications

Today in the US, hundreds of billions of tons of liquid petroleum products and trillions of tons of cubic feet of natural gas are crisscrossing the nation in the pipe that needs to be connected. For the majority of connections, the long weld neck flange is the one that does the job.

Weld-neck flanges

Weld neck pipe comes in two different neck sizes: long weld neck flange and standard weld neck flange. This blog will discuss the long weld neck flange and its use in industrial applications.

Meaning of a long weld neck flange

Long weld neck flanges (known as LWN) comes with an extended neck that acts as a boring extension. It is also longer compared to the standard weld neck flange.

Welded neck flanges are easy to recognize because they have a long tapered hub that reduces the size from the pipe to the fitting. Industrial long weld neck flanges are also useful in high-pressure industrial applications and high-temperature situations.

Long weld neck flanges are often useful in the petrochemical, gas, and oil industries. They come with nozzles and are useful in replacing the pipes. While a standard weld neck flange’s tip has a weld prep at its neck, long weld neck flanges come in a variety of lengths, with the most common being 9 inches, 12 inches, and 16 inches.

Unfortunately, lengths are based on the parts for every application, so there’s no universal standard length existence for these industrial-long neck flanges.

Long weld neck flanges come with the beveled flange to fit right with the pipe for added strength. Long weld neck flange connections help to improve the pipe flow. Additionally, piping systems are safer when reinforced with long weld neck flanges. It is the type of flange that helps balance the temperature and pressure changes in the liquid that flows in the pipeline.

Long weld neck flanges are often found as anchors in the water mains. The reason is that they can withstand higher pressures; you can connect larger networks of pipes, like those in a factory. You can also use long weld neck flanges in the expansion bends or to reduce or extend pipe sizes.

Why choose long weld neck flanges?

Industrial long weld neck flanges offer additional reinforcement that standard weld neck flanges do not. The long neck guides the pipe into the flange, giving them extra strength.

The extra assurance helps to ensure the safety of the structure, environment, and people when high-pressure fluids and high-temperature are involved. The structure reinforcement provided by an industrial-long weld neck flange is crucial to the stability and safety of industrial and high-pressure commercial systems.

The function of long weld neck flanges

The long weld neck flanges are useful in the following places:

Large pipe networks

Industrial long weld neck flanges are the safest and best choice, whether it is a water main, gas main, or another large piping network. Large networks need high pressure to keep everything in the pipes moving. It results in the strain on smaller pipes and may end up damaging if not accounted for correctly, and this is where industrial long weld neck flanges help.

Office complexes and apartment buildings

Like with any other large pipe network, high pressures are required to keep everything on the move. For that reason, you will commonly find long weld neck flanges that lead into these buildings.

Volatile or hazardous fluids

Wild temperature swings from sub-zero to near-boiling and high pressures may wear on the pipes and fittings used to transport the fluid. Long weld neck flanges may help cut costs by reinforcing the pipes used in high-pressure, high-temperature situations.


Industrial long weld neck flanges are game-changers for high-temperature, high-pressure, or otherwise dangerous amounts of fluid that need transportation. The added strength lent by these pieces helps to ensure the stability, security, and safety of the piping and structures that industrialists depend on daily.

Our team at Texas Flange is experienced, knowledgeable, and ready to assist you with any questions about the best products for your project. Give us a call today!

The Most Common Flanges in Pipe Welding: A Comprehensive Guide

The most used flange types per the ASME B16.5 are Blind, threaded, lap joint, socket weld, slip-on, and welding neck flange. Here you will find a short description and definition of each type.

common flanges

Welding neck flange

The easily recognizable long tapered hub of a welding neck flange provides an essential reinforcement of the joint. It is helpful for elevated, sub-zero, or high pressures applications.

The taper on this flange type offers a smooth relocation/transition of stress from flange thickness to pipe or fitting wall thickness. It is crucial under repeated bending conditions caused by the line expansion or other variable forces.

Slip-on flange

If we compare the slip-on flange with the welding flange, likely, it is not as durable. However, it has two-thirds less calculated strength under internal pressure and around one-third of the life span.

They come at easy installation and low material cost, best suited for low-pressure applications with little risk of leaking.

A few other advantages of the slip-on flanges are that it doesn’t require a sizeable longitudinal space in the line to be mounted. Also, they are less aligned with a wide variety of diameters available and do not require accurate cuts in the pipe.

Socket weld flanges

Socket weld flanges were initially developed for high-pressure, small piping. The static strength of the socket weld flange is equal to the slip-on flanges, but their fatigue strength is 50% high compared to the double-welded slip-on flanges.

Before welding, a space between 1/16” and 1/8” needs a creation between the fitting or flange and pipe. It allows you to expand the pipe on the inner side of the weld and reduces the residual stress, helping to prevent the crack weld on the fitting.

Lap joint flange

Lap joint flanges share the same features as the other flanges. However, it does not have a raised face. They are connected to a lap joint stub end.

These flanges are nearly identical to the slip-on flange, except for a curved radius as the bore. It helps accommodate the flanged portion of the stub end, and you can slide it over the pipe. The pipe is usually welded to the stub end, allowing free movement of the lap joint flange.

The strength is similar to the slip-on flange as they have a fatigue life of around one-tenth compared to the welding neck flanges.

Stub end

As a backing flange, a stub end will be used with lap joint flange applications. However, they are also helpful with slip-on flanges.

Stub ends are available in almost all pipe diameters. There are three different kinds available A, B, and C.

  • Type A is something you can machine to fit the standard lap joint support flange.
  • Type B is designed to be used with a standard slip-on flange.
  • Type C is useful with either a slip-on or lap joint flange.

Threaded flange

The top advantage of the threaded flange is that no welding is required in connection to the pipe. It is done using corresponding threads. However, a seal weld is sometimes applicable in conjunction with the flange’s threaded connection.

Threaded fittings are used exclusively in smaller pipe sizes up to around 4”; however, most pressure ratings and sizes are still available.

A threaded fitting or flange only suits applications that use a thicker wall thickness due to the presence of the thread.


This guide offers a solid foundation of the common top flanges in welding, however, with the wide range of stainless steel flanges and other flange materials available.

You can contact us if you want assistance choosing the right welding equipment for your welding project.


What Are Large Diameter Flanges and What Are They Used For?

The large diameter weld neck, slip-on, and blind are two types of the commonly used flange in large assemblies. Butt welding flange and slip-on flange styles are known common large diameter flange options, although the application and structure range of the flat welding large diameter flange and the butt welding large diameter is different.

About large diameter flange

Large diameter flat welding flange has less high-pressure suitability compared to its weld neck counterpart. The basic ring style is suitable for the occasion of low pressure. The butt weld category of the flange is known as a weld neck flange. It suits the occasion of high temperature and pressure as defined in the ASME B16.47 code. Large diameter flanges are widely popularized and used in the sewage treatment industry, wind power industry, chemical industry, and machinery industry.

The material used to manufacture large flanges

The most common material used to manufacture large diameter flange is carbon steel that is forged carefully and of which surfaces have been machined. These flanges are made in multiple ways. Some come with raised faces, while some do not. Almost every type of flange has a seal attached to it to preclude any leaks from the pipeline.

The ASME/ANSI B16.47 Large Diameter Steel flanges include NPS 26 through NPS 60. The standards cover testing, marking, tolerances, dimensions, materials, temperature ratings, and pressure ratings for flanges of this size with rating class designations 2500, 1500, 900, 600, 300, 150, and even 75# for Series B compact style flanges.

Uses of large diameter flanges

The versatility of large diameter flanges, alongside using it with larger pipes, has enabled their installation with applications including engineering units, food industries, gas and oil processing, power plants, construction, cement manufacturing, etc.

Benefits of large diameter flanges

The following are benefits of large diameter flanges:

Properly installed large diameter flanges are corrosion resistant and come with a wide variety of media uses.

They are easy to fit in any climate, and the reason is their simple installation. They can be installed easily, even underwater, given the large sealing surface areas.

Elastomeric sealing gaskets expand the life expectancy of these flanges to at least 50 years.

They come with long-term protection against corrosion, abrasion, and impact to ensure continued reliable performance when properly manufactured.

The welding process of large diameter flanges

Manufacturing of large diameter flanges is usually used in some tank equipment and large-scale furnace to strengthen and connect. The kind of equipment is not typically made as a commodity production run, but rather belongs to the small-batch or single-piece production. The conventional process is to cut the circular plate as per the size of the whole steel plate for plate flanges. After, it needs to be cut off the inner circle on the circular plate. The process method is simple but requires operation space, and large black size, so it is helpful to add a large diameter flange that will cause low economic benefit and low material utilization. Forgings are required for large diameter slip ons with hubs and weld necks.

The flange must be drilled with bolt holes needed to match with a rubber sealing ring and another flange that is added in the middle. To make sure about the sealing effect, the flatness tolerance of the flange is usually required to be higher by end-user applications, and the overall thickness of the flange plays a supporting role. Therefore, dimensional tolerance and roundness of the outer and inner holes of the flange are not as high as smaller flanges.


Texas Flange creates a significant volume of different diameter flanges for the biggest jobs in the industrial and energy fields. We can create a variety of different flange dimensions for custom flange types, configurations, and sizes using numerous suitable materials of construction for every application.

If you need assistance and want to learn more about the different flange sizes, contact Texas Flange today!

Complete Guide to the Most Common Flanges in Pipe Welding

The industry-accepted flanges in pipe welding according to the ASME B16.5: Slip-On, Blind, Threaded, Lap Joint, Socket Weld, Welding Neck flange. Below you will find a short definition and description of each type.

Welding Neck Flange

It is an easily recognizable long tapered hub of a welding neck flange that provides a crucial reinforcement of the joint. It is useful for applications that involve sub-zero and elevated temperatures where the joint will be under a particular amount of stress.

This type of flange also offers a smooth relocation/transition of stress from flange thickness to fitting or wall thickness. It is beneficial under conditions of repeated bending, caused by other variable forces or line expansion.

Slip-on Flange

Slip-on flange compared to the welding neck flange is more easily installed to fit with your pipeline length restrictions. It has around two-thirds less calculated strength under internal pressure and around one-third life span to the weld neck.

However, they are easy to install and come at a low material cost which is, therefore, better suited to low-pressure applications with little risk of leaking.

Slip on Flanges

Other advantages of slip-on flanges are that they do not require a large longitudinal space in the line to be mounted. They are much less difficult to align with a wide variety of diameters available and do not require accurate cuts in the pipe.

Socket Weld Flange

Socket weld flanges are initially developed for use in high-pressure and small-size piping. With the static strength equal to the slip-on flanges, the fatigue strength is considered to be somewhere around 50% greater than double-welded slip-on flanges.

Before welding, a space of between 1/16” and 1/8” must be created between the flange or pipe and fitting. It allows the expansion of pipe on the inner side of the weld and reduces the residual stress, therefore preventing weld cracking on the fitting.

Lap Joint Flange

Lap joint flanges share the regular features as the other flanges mentioned, however, it does not have a raised face. The flanges are nearly identical to the slip-on flange, except for a curved radius at the bore and a larger hub to accommodate the stub end.

It is to accommodate the flanged portion of the stub end properly and then slide over the pipe. The pipe is usually welded to the stub end to allow free movement of the lap joint flange.

Stub End

Stub end is helpful with lap joint flange applications as a backing flange, however, they are also sometimes beneficial with the slip-on flanges. Stub ends are available in almost all pipe diameters. You can find three different types available that are A, B, and C.

  • Type A can be machined to fit the standard lap joint support flanges.
  • Type B is designed to use with a standard slip-on flange.
  • Type C is useful with either a slip-on or lap joint flange.

Dimensional tolerances and dimensions are defined in the ASME B.16.9 standard. Light-weight corrosion-resistant stub ends (fittings) are defined in MSS SP43.

Threaded Flange

The main advantage of the threaded flange is that no welding is essential with a pipe connection. It means that it is done by corresponding threads. However, sometimes a seal weld is also applied in conjunction with the connection of the flange thread.

Threaded fittings today are useful almost exclusively in smaller pipe sizes up to around 4.00”, however most pressure and size ratings are available per our catalog, and the dimensions of B16.5

A threaded fitting or flange is only suitable for applications that use a thicker wall thickness due to the presence of the thread. A pipe system with a thin wall thickness has no space for threading.


Two types of threaded flanges are available, one is useful to seal the two pipe ends with a sealing surface and lens pad. It is useful mostly in the production of ammonia until recently. The other type is a more standard setup, sealed with two flange sealing faces.

Flange welding equipment ranges from Head and tailstocks, welding positioners, and pipe rotators for positioning of pipe welding.

If you want any assistance choosing the right welding equipment for your welding project, you can contact us.

5 Key benefits of Flanges

Flanges are helpful to connect pumps, valves, pipes, and other parts to form a piping system. Flanges are typically welded or thread screwed to connect. The use of flanges allows a person for maintenance and easy repair of the pipe system. Instead of taking out the whole pipe for inspection, the smaller section of the pipe can be inspected to find the fault with the help of a flange. The flange connection point allows for reinforcement of the system, as well as pipe cleaning and easy inspection.

You can join the two flanges together by bolts using a gasket between them for seal. Most steel flanges are used in the gas industry, oil industry, petroleum industry, and chemical industry. The essential types of flanges are threaded flange, lap joint flange, blind flange, socket flange, weld neck flange, and slip-on flange. Some special types of flanges are special bevel neck flanges, long welding flanges, nipoflange, reducing flanges, expander flanges, and orifice flanges.

Materials used in flange

High performance yield strength steel: ASTM/ASME A694 F42 , F52, F56, F60, F65, F70

Low temperature steel: ASTM/ASME A350 LF2.

Stainless steel: ASTM/ASME A182 F321-321H, F347-347H

Stainless steel: ASTM/ASME A182 F316-316L-316H-316LN-316N-316Ti

Stainless steel: ASTM/ASME A182 F304-304L-304H-304LN-304N

Chrome alloy steel: ASTM/ASME A182 F1-F12-F11-F22- F5-F9- F91

Carbon steel: ASTM A105, ASTM A105N, GB 20, C22.8.

Flange dimensions

5 Key benefits of Flanges

The flange dimensions vary by style, and each flange type comes with a standard dimension definition. The dimension of the flanges is the same worldwide for repair and maintenance work and smooth operations. The dimensions are usually published in both inches and millimeters.

The basic dimensions of the flange consist of outside diameter, number of bolts, thickness, and hub detail. The bolts are usually located on the front outside the flange. The gasket used between the two flanges has the same bolt holes and size as that of the flange facing.

Benefits of the flanges

Even though you can find a specified application where the flanges and fittings are the only practical choice, flanges also provide benefits to the piping system that traditional hydraulic fitting types do not. For example, in the larger OD applications, flanges are often unable to connect to the pipe and component ports more easily compared to the adapters or threaded fittings. Most importantly, in most severe service applications on mobile construction equipment flange connections are suitable for:

1. Easy assembly at tight spaces where wrenches might not have clearance if you install traditional flange fittings. They are more easily assembled with moderate torque.

2. Hard-to-reach areas where you need flexibility, you can eliminate the need for adapters in the hose line, pipe, or tube.

3. Pipe connections, tubes, or large hose connections where you find high pressure, vibration, or shock pressures are present, that could more easily damage the traditional large hydraulic fittings.

4. Making connections allows for easy maintenance in rigid lines like metal tubes or continuous pipes.

5. Reduce the chance of components becoming loose in rigorous hydraulic applications.

The use of flange connections at high-pressure circumstances and larger size allows easy assembly of overusing the larger fittings. The flanges come with zero-clearance assembly, easy reconnecting and disconnecting for maintenance of hose, manifold, and tube connections could be much faster and provide the ability for more accurate torque of the bolts as opposed try achieve the proper torque of a large fitting. Flange fittings and flange connections are less likely to loosen compared to a standard hydraulic fitting when there is a proper load distribution of clamping around the flange head. You may think of it as bolting the wheel of your car onto the brake or hub drum disk. If you do not tighten the lug nuts, the star pattern wheel will not tighten and maintain a connection. It may cause warping of the brake drum, rotor, or brake disc.


Flange connections are one of the best options for pipe end connections that have bends that are subjected to very high lateral forces inclined to cause the loosening of the assembly. The five benefits mentioned above clearly define the key benefits of the flanges.

If you need assistance to know more about the flange bolt tightening or choosing the right type of flange, contact Texas Flange today!

What Are Different Grades of Carbon Steel Flanges?

Iron and carbon steel are the main components behind the manufacturing of carbon steel flanges and end flange connectors. These flanges help connect pipes to valves, pressure vessels, pumps, or other equipment. Grades of steel products change depending on the material ratio, such as the carbon content. Many grades of carbon steel flanges e.g. ASTM A105, ASTM A182, ASTM A694, ASTM A516, and ASTM A350 are available. The content of the carbon range is about 1% to 2.1% in weight in the carbon steel flanges.

The increase of carbon element content makes the steel sturdier and stiffer after the heat treatment, and it also becomes less ductile. Without the heat treatment, higher carbon will reduce weldability.

Carbon steel A105 flanges

The Carbon Steel A105 flanges are the forged carbon steel piping components that you can use for valves, flanges, and fittings in pressure systems at higher temperatures and ambient service conditions. You can reliably operate Carbon Steel A105 flanges under temperatures from 0 degrees to 550 degrees. They are helpful in hydro-carbon and marine engineering processes. You can also use it in nuclear power plants, oil and gas equipment, valves manufacturing, petrochemical plants, pumps manufacturing, and heat exchangers. There are many kinds of flanges like blind flanges, weld neck flanges, plate flanges, and much more.

Carbon steel A350 LF2 low-temperature flanges

The Carbon Steel A350 LF2 Flanges encompass many ring-rolled and carbon flanges, valves, low-alloy steel forged, and forged fittings for low temperatures. The flanges are extensively known for their durability, strength, pressure resistance, and temperature rating. The Carbon Steel A350 LF2 Flanges provide maximum machinability when hardened, forged, or normalized. It ends up gaining moderate strength and offers a leakage-proof connection at lower costs. These flanges are usually more in demand than conventional austenitic stainless due to their property of higher hardness versus cost.

Carbon steel in low alloy A182 Flanges

The grade of carbon steel flanges are helpful in stainless steel pipe flanges, forged fittings, valves, rolled alloy, and other high-temperature services. The Carbon Steel low chrome A182 Flanges are one of the outcomes of the ideal selection for low corrosion applications. These flanges do not get worn out as quickly. The use is widespread, especially in the paper, chemical, and petroleum industries. The features of this flange type make it the most reliable product that stays long and does not require repairing soon after the installation. If purchased from the right place, you can ensure the durability of this product.

Carbon steel A694 flanges for high yield service

It is the most stress-reliant carbon steel flange material in comparison to the above three. It is stringent to the high-pressure fluid transmission of gas and oil piping. Most of the property is steel-grade for high-yield service. Manufacturers need to develop well-built steel to withstand both high and cryogenic temperatures. With the increase in carbon content, the steel gets heavy after the heat treatment. It also becomes less ductile. If there is a lack of heat treatment, the chances become higher for carbon to reduce the ability to weld.

About forged steel flanges

There are many ways you can manufacture flanges, the most prominent ones being casting and forging. Flanges are basically a plate-like round device affixed at the end of the fitting, valve, pipe, etc which helps to put a piping system together. Manufacturers develop flanges of many materials that match the material that you use for pipes and fittings. There are usually two ways: Forged carbon steel and cast iron for older, less critical applications.

Forged steel is the excellent mechanical property of almost any flange product. The process of manufacturing happens with carbon steel, alloy steel, or stainless steel. The raw materials are beaten and cut into shape via hammers and presses, which helps to get rid of defects and blocks. A flange helps connect pipes to each other, often with an attachment of a valve to the pipe end. It is functional for the flange on inlets and outlets.

General grades of carbon steel flanges

Below are few common grades of carbon steel flange:

ASTM A694 F42, F46, F48, F50, F52, F56, F60, F65, F70 high yield

ASTM A350 LF1, LF2 CL1/CL2, LF3 CL1/CL2 low temp

ASTM A105N (SA105N) forged

ASTM A516 Grades 55, 60, and 70 plate

How to prevent carbon steel flange from rust?

Carbon steel can get rust, but you can prevent it using the following solutions:

1. Oil varnishing: It helps to lubricate the carbon steel. Oil forms a protective barrier against rust and allows them to move with friction.

2. Anti-rust painting: Painting a carbon steel flange helps to cover metal components in a protective layer. It helps to prevent moisture from reaching the metal and therefore prevents rust and general corrosion.

3. Electric zinc-coated (Yellow or white zinc): Galvanising or electric zinc-coating is one method to prevent rust. It is easy to stop the reach of water and oxygen underneath the metal by coating it in a thin layer of zinc.


It is always better to get in-depth knowledge about the product you are willing to buy. You can find different grades of carbon steel flanges mentioned above from us. The guide will help to select the right one as per the requirement.

If you want any specific flange information, get in touch with us today!

Guidelines for Selection of Various Types of Flanges

Flanges are one of the most vital components in a piping system. They connect pipes, pumps, valves, and other equipment to form a complete piping system assembly. Flanges also enable seamless modification, inspection, and cleaning of these systems.

Some aspects to consider when selecting flanges are:

Material grade

Flange face type

Flange finish

Flange thickness and dimensions

Here’s a quick guide to selecting the various types of flanges based on their applications, material standards, and ASTM standards.


Ring-Type Joint vs. Raised Face

Most pressure vessel flanges fall under two categories – ring-type joint and raised. Many manufacturers consider ring-type joint flanges more efficient as they give grooves cut into their faces instead of a plain gasket between connecting flanges. Upon tightening, a rated metal gasket is compressed into the grooves, providing an extremely tight and leak-proof seal for higher stress service.

The major benefit of using a ring-type joint flange is that the groove is within the flange. When the bolts are tightened, the ring centers itself. An API type flange is a common type of ring-type joint flange.

Raised face flanges are excellent for concentrating more pressure on a smaller gasket area. It increases the joint’s ability to hold pressure. These flanges are widely used in process plant applications. The gasket surface of these flanges is raised above the bolting circle face, hence the name.

Which One to Use: If you need a flange for high-pressure and temperature situations, a ring-type joint flange can be an ideal pick. It can be used for petroleum industry applications, oil fields, and pipework assemblies. On the other hand, raised face flanges are versatile and can be used in all high or low pressure and temperature situations.

Weld Neck Flanges

Weld neck with matching bevel to pipe

A weld neck flange, also known as a tapered hub flange or buttweld hub flange, comprises a circular fitting around the base along with a protruding rim and the pipe connection end. These flanges are always made from forged construction and then butt-welded to a pipe. It transfers the stress from the flange to the pipe in a more seamless manner with regards to load bearing factors from an engineering design perspective.

You can use weld-neck carbon steel flanges in hostile environments with extreme sources of stress, such as pressure and temperature. These flanges can bear pressures up to 5,000 psi or higher. Weld neck flanges are available in all steel material grades, such as stainless steel, carbon, and alloy. Be sure to choose weld neck flanges with an ASME B16.5 rating for optimal field service.

Blind Flanges

The purpose of a blind flange is to block off a section of a pipe or nozzle by covering or closing its end. You can also utilize blind flanges to get easy access to a vessel or line’s interior if it needs to be reopened after getting sealed.

Understandably, blind flanges are suited for specific cases. These flanges are commonly available as both raised flat (RF) and flat faced (FF) styles. They’re best suited for waterworks, petrochemical, pipe engineering, and public services.

As far as material standards are considered, these flanges should follow the same standards as other flanges, such as weld neck flanges. Stainless steel flanges are ideal for corrosive environments where stainless weld necks are often installed with stainless blind flanges to match.

Slip-On Flanges

Slip on Flanges

Slip-on flanges slip over the pipe or tube to which you want to join. These flanges are manufactured with high precision to ensure their inside diameter is slightly bigger than the outer diameter of the pipe. These flanges are then linked to the pipe using a “fillet weld” at the inside, outside, top, or bottom of the flange. The fillet weld makes sure the joint is firm and properly sealed.

Slip-on flanges are best suited for low-pressure applications. They’re available as both raised and flat-faced flanges and are easier to align than weld neck flanges. These flanges are ideal for design temperatures below 230-degree Celsius and a corrosion allowance of more than 3 mm in comparison to weld necks. For severe cyclic conditions, look for flanges ASME B31.3 or ASME B16.5 Class 600 or higher ratings.

Lap Joint Flanges

A lap joint flange assembly consists of two components: a stub end and a backing flange. A pipe is welded to the stub end with a gasket, while the backing flange isn’t welded and is free to move and rotate. It enables you to get the desired alignment when joining it with another pipe or elbow.

You should consider lap joint flanges if your piping system requires regular inspections, cleaning, or dismantling. These flanges can align bolt holes and swivel around, simplifying the assembly of stiff piping with larger diameters. They are best suited for low-pressure applications and may not work well in high load conditions.

Wrapping Up

Each flange is different and has unique applications. It’s critical to understand the features and characteristics of each flange to find the one that best suits your needs.

If you need assistance in selecting the right flange type, get in touch with Texas Flange today!