What is the Function of Flanges and How Do They Work?

The flange industry is wide, and it offers customers a reliable way to connect pipe systems with the various valves, equipment, and other components of virtually any processing system. Flanges are the second most used joining method after welding.

Custom Pipe Flange Fittings

If you use flanges, it adds flexibility when you need to maintain piping systems. It also allows for easy disassembly and improved access to system components.

A typical flanged connection is comprised of three parts:

  • Bolting
  • Gasket
  • Pipe flanges

In many cases, specific bolting and gasket materials are made from the same or approved materials as the piping components you wish to connect. For example, stainless steel flanges are the top choice among some of the most common flanges. However, flanges are available in a wide range of materials, so matching them with your needs is crucial.

Other common flange materials include Chrome Moly, Inconel, Monel, and many others, depending on the application.

The best option for your needs depends on the system in which you intend to use the flange and your specific requirements.

Common flange types and characteristics

Flanges are not a one-type-fits-all kind of solution. If we keep the sizing aside, matching the ideal flange design to your piping system and intended usage will help to ensure optimal pricing, a long service life, and reliable operation.

Here are the most commonly available flange types:

Threaded flanges

It is also known as a screwed flange and has a style with thread inside. The flange bore fits with the matching male thread on the fitting or pipe. The threaded connections mean you can avoid welding in many use cases. If you simply match the threading o the pipes, you wish to connect.

Socket-weld flanges

Ideal for small pipe diameters in low-pressure and low-temperature scenarios, socket-weld flanges feature a connection where you place the pipe into the flange and then secure the connection with a single multi-pass fillet weld. As a result, it makes the style simpler to install compared to other welded flange types while avoiding the limitations associated with the threaded ends.

Slip-on flanges

Slip-on flanges are quite common and are available in large-size ranges. It can accommodate systems with high flow rates and throughput. You intend to connect if you match the flange to the outer pipe diameter. Installation is slightly more as you will need to fillet the weld on both sides to secure the pipe flange.

Lap joint flanges

Lap joint flanges require butt welding of the stub end to the fitting or pipe with a backing flange to create a flanged connection. The design makes this style popular for use in systems with physical systems or space that requires frequent maintenance and dismantling.

Weld neck flanges

Weld neck flanges need butt welding for installation. However, its performance, integrity in the systems with multiple repeat bends, and the ability to use them at high temperatures and high pressure make them a top choice for processing piping.

Blind flanges

Useful for isolation or terminating piping systems, blind flanges are essentially boltable blank discs. When you install them properly and combine them with the correct gaskets, it can achieve an outstanding seal that is easy to remove when needed.

Specialty flanges

The flanges types listed above are quite common. However, various specialized flange types are available to suit various environments and uses. Other options include reducing flanges, orifice, expanding flanges, weld flanges, and nipo flanges.

Flange Facing Types: Making the connection

The design is just a start when you consider the ideal flange for your piping system. Face types are another characteristic that greatly impacts your flanges’ service life and final performance.

Facing types determine the gaskets required to install the characteristics and the flange related to the seal created.

Common face types include:

  • Flat Face (FF)
  • Raised Face (RF)
  • Ring Joint Face (RTJ)
  • Tongue and Groove (T&G)
  • Male & Female (M&F)

Most face types offer one of the two finishes: smooth or serrated. Choosing between the options is crucial as it will determine the optimal gasket for a reliable seal. In general, smooth faces work best with metallic gaskets, while serrated faces help create stronger seals with soft material gaskets.

Flanges Dimensions: The Proper Fit

Apart from the functional flange design, flange dimensions are the most likely factor that impacts the flange choices when updating, maintaining, or designing a piping system. First, however, you must consider how the flange interfaces with the pipe and the gaskets in use to ensure proper sizing.

Common considerations include:

  • Nominal bore size
  • Pipe size
  • Bolt circle diameter
  • Thickness
  • Outside diameter

Flange classification and service ratings

The above characteristics will influence how the flange performs across various environments and processes.

Flanges are often classified based on their ability to withstand pressures and temperatures. It is designated using a number and either ‘class,’ ‘lb,’ or ‘#’ suffix. These suffixes are interchangeable but will differ based on the vendor or region.

Common classifications include:

  • 150#
  • 300#
  • 600#
  • 900#
  • 1500#
  • 2500#

Flange markings and standards

To make the comparison easy, flanges fall under global standards established by the ASME (American Society of Mechanical Engineers) – ASME B16.5 & B16.47.

If you are attempting to verify or replace the existing parts, all flanges must include the markers, typically on their outer perimeter, to aid in the process.


The above guide offers you a solid foundation of the basics of flange design and how to choose the ideal flange for your piping system. However, with a wide range of stainless steel flanges or other available flange materials, it is impossible to list every consideration, detail, or configuration.

You can contact Texas flange if you want the best quality flanges or have any queries regarding the flange function.

5 Best Tips to Use Steel Pipe Flanges For The First Time

A pipe flange is a mechanical device that serves the purpose of joining the pipes together. It can be in the form of a welding neck where it is welded to a pipe or other butt-weld fittings.

The threaded flange or flange collar is screwed to the flange with a companion pipe. Other methods include using a lap joint to make connections using a stub end, as well as the common slip-on and socket weld connections.

Steel pipe flanges

Here are five tips for using the steel pipe flange for the first time:

Slip-on flanges for low-pressure services

The preference of slip-on flanges is mainly by the users who prefer flanges that are easy to use, have less installation time, and have low cost.

In addition, they are helpful for non-critical low-pressure services like firewater, cooling water, and other non-challenging pipework owing to their strength being approximately 1/3 lower than that of a weld neck flange, depending on the assembly. The pipe gets welded to the flange hub and bore.

If you want to check on the integrity of the slip-on connection, a magnetic particle, a simple visual test, or a PT test are the approaches you can follow. You can use the slip-on flanges, which come in a variety of sizes greater than NPS ½ (DN 15).

Socket weld flanges in high-pressure pipe works

If you do high-pressure pipework below 2 inches (DN50), a socket weld flange is preferable when space is constrained. It would help if you filleted weld the pipe to the socket weld flange hub. A good welding flange experience is crucial to make the connection since a radiographic examination on the fillet weld is not easy to execute.

If, however, the connection is visual and critical, examination alone will not be enough if it carries out the magnetic failure or penetrates particle tests to check the connection strength.

Lap joint flange in high-cost material pipelines

The working of lap joint connections is good for pipelines that are in high-cost materials such as stainless steel and nickel alloys. It dramatically reduces the total cost of all flanged connections which is required. The stub end, which has been welded to the pipe, and the backing or lapped flanges are used to make a lap joint connection.

You may, for instance, use the stainless steel stub end combined with a carbon steel lap joint flange for a good welded connection at lower costs. This is becoming an increasingly common alternative as the volatility of steel prices becomes an issue.

Connecting weld neck flanges to the butt weld for good performance

There is a tapered hub on the weld-neck flanges. It comes with an end that’s finished as a butt weld and can be connected to butt weld pipe and fittings. You can examine the weld’s quality with ultrasound radiography or visually do it.

The welded connection of weld neck flange or pipe flange features good fatigue as well as mechanical stress performance.

Skilled professionals execute the pipe flange joint process

Trained personnel must be the ones to execute flange joint seals. It helps to prevent dangerous leaks from happening in the pipeline. With the first time use of steel pipes, a properly trained engineer must be the one to execute flange ring joint connections and reference the correct bolt torque data.


Steel pipe flanges are often the best solutions to your multi-stage pipe assemblies, but the material grade is also of concern. Stainless steel is a corrosion-resistant, durable, strong metal, making it an excellent choice for flange fittings in the gas and oil industry when carbon steel will not suffice. If you want more information on steel pipe flanges, contact Texas Flange.

Specification and Types of Carbon Steel Flanges

The manufacturing of carbon steel pipes happens by using various techniques that produce a pipe with various characteristics. The carbon content present in the carbon steel pipe can be up to 2.1 percent of the weight of the total alloys.

An increase in the carbon percentage in the alloy helps to increase the tensile strength and hardness of the metal. The black carbon steel jacketed pipe would lose its ductile properties, even with a rise in the percentage of carbon.

About Carbon Steel Flanges

The manufacturing of Carbon Steel Flange is from various carbon steel grades. Common standards include DIN (2533 and other subspecs), MSS SP-44, ASTM A105N, and ASTM A694. They accompany pressure ratings from class 150 to 2500 in imperial and PN10 to PN40 for metric.

Carbon steel is the kind of steel that contains a carbon content of up to 2.1% by weight. AISI defines carbon steel as:

Maximum Mn 1.65%, Si 0.06%

Specified minimum of Cu shall not exceed 0.04%.

No alloy element (minimum content) is required for Cr, Mo, Ni, Ti, Va, etc.

With the increase of carbon element content, the steel will become stronger and sturdier after heat treatment. On the contrary, it becomes less ductile, which may be useful for your application. A high amount of carbon will reduce weldability if it is created without heat treatment.

Carbon steel may include alloy steel if not used as stainless steel.

Specification and Types of Carbon Steel Flanges

Various specifications of carbon steel pipes

Carbon Steel Pipes are available in a wide range of sizes of about ½” NB to 48” NB. The manufacturing of carbon steel pipes happens in many standards, namely, ASTM A/ASME SA 333 Grade 1,6; API 5L – PSL 1 Gr. A, B, X42, X46, X52, X56, X60, X65, X70; ASTM A/ASME SA 53 Grade A, B; ASTM A/ASME SA 106 Grade A, B, C.

The design of carbon steel pipes ranges as per the level of thickness. The range starts from SCH 40, SCH 80, SCH 160, or so on. The CS pipes find their applications in the industries like General Engineering, Pressure Vessels, Sugar, Steel, Boiler Equipment, Petrochemicals, Oil Refineries, and Power Generation (Thermal/Nuclear). Production of most carbon steel pipes is from Grade B steel for years and has a minimum yield strength of 35,000 psi.

Different types of Carbon Steel Pipes

Carbon Steel pipes are manufactured in various types like:

  Carbon Steel ERW Pipes

They have various features like intricate detailing, precision-engineered, appropriately structured, corrosion resistance, lightweight, economical and more. The ERW pipes are used in General & Heavy Engineering, Transmission Towers, Coal & Mining, Oil & Petro Chemicals, Boilers & Pressure Vessels, Automobile, and Ship Building.

  Carbon Steel Welded Pipes

The pipes are helpful during high-pressure conditions. In a wide range of industries like transport of waste and water, carbon steel pipes, chemical manufacturing, high-pressure applications, and oil & gas industries commonly use carbon steel pipes.

  Carbon Steel Fabricated Pipes

They offer tensile strength with corrosion resistance and high durability. The carbon steel fabricated pipes are useful in various industries. The industries include the following: desalination industry, ships industry, food industry, pulp and paper industry, energy industry, metallurgical industry, oil & gas industry, and chemical industry.

  Carbon Steel ASTM A335 Pipes

The ASTM A335 Seamless pipe consists of carbon steel with a minimum tensile strength of 415 MPa and minimum yield strength of 205 MPa. The material has high resistance and high durability to wear and tear. The manufacturing is of molybdenum, chromium, silicon, sulfur, phosphorus, manganese, and carbon. The composition of the ASME SA335 Grade Chrome Pipe helps give the characteristics of pipes. It includes corrosion resistance, hot hardness, wear resistance, stiffness, and strength.

  Carbon Steel Seamless Pipes

It contains more iron and carbon in its composition. The quality of the pipes depends on the materials present in them. It has copper, manganese, and trace amounts of silicon. Therefore, the Carbon Steel Seamless Pipe material is sturdier and resistant to stress. In heavy-duty facilities, the features make the pipes applicable.

  Carbon Steel LSAW Pipes

It has some fine features such as easy installation, rustproof and seamless finish. These LSAW pipes are expensive and not widely popular in lower value non-energy applications like water pipelines.


The specifications and types of carbon steel flanges are listed above. The blog will help you to get a better understanding of both the aspects of Carbon Steel flanges.

To learn more about stainless steel super duplex flange, visit https://www.texasflange.com/carbon-steel-flanges/.

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!

The Benefits and Uses of Stainless Steel Flanges

Flanges make a vital connection in industries when it comes to valves, piping, and other equipment. They also provide an easy point of access for modification, inspection, cleaning, and necessary repairs. A flanged joint provides a strong seal in a closed system.

In heavy industries, the flanges need to be resilient, and they prove to be the weak point in a system if not selected properly. It is therefore essential to ensure that the flanges you choose are up to the task.

Use of stainless steel flanges in industries

Stainless steel comes in with the same standard carbon and iron compositions, along with nickel and trace amounts of other elements. But one thing that makes it stand out is that it also contains chromium. It is an alloy that gives corrosion resistance, and therefore a stainless finish.

Most of the more expensive grades come with high resistance to corrosion. Chemicals, rust, and other environmental factors take a toll on metals. It is the reason why the flange choice must be the one that is resistant to these factors. Stainless steel easily outperforms comparison to other entry-level metals that are variants of carbon steel.

The functioning of stainless steel is that it is durable and incredibly sturdy for most applications, and that can it withstand immense pressures. If you compare, aluminum may come as a cheaper option, but it is softer and unreliable under heavy stress and extreme temperature variations.

Any piece or system of equipment is only as robust as its weakest part. Welds and joints are known to be weak points and need to withstand very high pressure. The correct grade of stainless steel flange is helpful to ensure that no deformation or warping would compromise the system.

Benefits of using stainless steel flange

The Benefits and Uses of Stainless Steel Flanges

Stainless steel flanges are essential in industries like beverage, food, water, gas, and transport. It also provides several benefits, a few of these including:

Corrosion and stain resistance:

Stainless steel flanges are excellent in a wide range of atmospheric environments and many corrosive media. It is resistant to crevice and pitting corrosion in warm chloride environments. It is also resistant to corrosion that cracks below approximately 60°C.

Versatility and strength:

You can add different materials like nitrogen, molybdenum, nickel to stainless steel to enhance the corrosion-resistant properties. ASTM A182 specified flanges can handle extreme temperatures and have higher strength at elevated temperatures above 500°C up to about 800°C.


Stainless steel flange are one of the excellent choices for commercial establishments. The reason is that the material has a naturally elegant and shiny look compared to weathered carbon.


When you use stainless steel flange, you buy durable products that will help your projects last longer for decades. It is a reliable material that is easy to install and maintain. Stainless steel is one of the low-maintenance metals because of its non-corrosive properties. It is unlikely that it needs a replacement for decades.


You can use stainless steel in all types of water. Applications include drinking water in public supply. The flanges have excellent resistance to the full range of potable waters, including various chloride levels.

Stainless steel is not a petroleum product in and of itself. It doesn’t need to be lined or coated with any materials at all, unlike some other materials. When you want to dispose of or replace the steel flanges, they are scrap-friendly and recyclable – helpful in reducing the environmental impact.

Material benefits:

The combination of corrosion resistance with high strength allows a reduction in flange weight and thickness. Stainless steel can withstand even high flow rates – over 40m/s – that makes it capable of resisting even long-term exposure to the elements in almost any environment.

Economic benefits:

Stainless steel flanges are low maintenance and do not have an additional coating for outdoor and indoor applications. The expected lifetime of a stainless steel system is for more than 50 years. It helps in reducing the maintenance, replacement, and downtime costs over the life of the installation.

No blasting, painting, or welding:

When you use flanges, there is no requirement to weld the pipe spools. In the same way, blasting and painting also become unnecessary, unlike other methods and fittings.

Ease of modification and fast fabrication:

Flange use can help in speeding up the process. If you are all ready to take the benefits of flanges, you can look here to get a complete range of stainless steel flanges with us.



Even though you will find a range of flanges in the market, we offer you the best quality product for your particular application. Nothing can beat steel flanges, even if it is the carbon steel flanges. As you have already read about the uses and benefits of stainless steel flanges above, we hope you’ve now received good knowledge about steel flanges and whether they are the best option for you.

If you want any specific information, then contact Texas Flange today!