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Things to Know Before Buying Flanges

Flanges are one of the most crucial elements of assemblies in the oil and gas industries, but it is an undeniable fact their selection can be a bit mysterious to the average consumer. Most piping systems today rely on flanges to function correctly. However, flange maintenance is something that most people don’t understand properly. The more you know about flanges, the less risk there will be in operation.

Below are a few of the facts that you might not be aware of about flanges. They are the key things that are necessary to help continue the functioning of components in pipeline service industries.

Offer Different Grades Of Material

You need to buy the best material grade for your application. When corners are cut, things can become challenging and can cost even more in repair and maintenance. You should invest in purchasing flanges that suit your project’s overall needs.

So, what are the different grades of material?

The material grade comes in with a combination of letters and numbers and is indicative of the use, chemical composition, and mechanical properties of the product. You must study the material grades very carefully before you decide to purchase.

Also, note that if the placement of flanges is not correct, the assembly can fail. It may even result in people, especially workers, getting injured or even claiming life. You must pay careful attention to the types of flanges, their steel and manufacturing origins, and the manufacturing quality.

Things to Know Before Buying Flanges

There are a few key material grades for pipe flanges. These are:

1. ASTM A182 F51, ASTM A182 F53/55 (super duplex and duplex flange), and high grades (Monel Hastelloy, Inconel flange).

2. ASTM A182 F321, F316, F304 (stainless steel flange)

3. ASTM A182 F11 to F91 (alloy steel flange)

4. ASTM A694 (MSS SP-44 high yield carbon steel flanges for line pipes)

5. ASTM A350 LF1, LF2, LF3, LF6 (CS flange for lower temperature service)

6. ASTM A105 (carbon steel flanges for normal to high-temperature services)

The flange and pipe material must match as per the ASTM piping materials selection charts.

Manufacturing from different materials

Common materials include bronze, cast iron, aluminum, stainless steel, carbon steel, and plastic (although we do not deal in polymers, nor are they included in B16.5). At times, the different materials are beneficial in creating the same single flange types.

Different forms of flanges

Flange distributors offer many types of flanges. There is no single type of flange which suits every situation. The selection of the flange must happen carefully by taking care of all the measures. If the wrong flange is used in the project, it can be disastrous.

A few popular pipe flanges include orifice, socket, threaded, lap joint, slip-on, weld neck, and blind. Each of these flanges serves different purposes.

The meaning of an orifice flange is that it must house an orifice meter that can easily track the speed of flow within a pipe, as well as temperature and pressure. It is one reason why the orifice meter has become one of those complex parts to create. On the other hand, blind flange is one of the most uncomplicated flange designs and pairs well with a ring flange which does not require much to assemble.

If you need multiple kinds of flanges in a single project, it would be wise to work with a single provider for all of them. It helps avoid sourcing issues and ensures that all the products are made with the same quality standards.

Casting and forging of flanges

There are two kinds of methods that are useful for the creation of flanges. These include forging and casting. Both the cast and forged flanges may work well, but each production method has certain disadvantages and advantages. Cast are seen as outdated and not useful for high-stress service.

The creation of cast products can be seen when they pour the molten metal into a mold or vessel to create the desired shape. Billets and steel ingots are useful when it comes to the creation of forged products. Exposure to thermal and mechanical pressures helps them to manipulate different shapes.

The issue with the cast flanges is that they are much more prone to internal defects. It means that you cannot use them in extremely high-pressure situations as there is a possibility of sudden failures without any warnings. As there would be a risk of internal flaws, the cast flanges are also most likely to be heavily affected by corrosion.

In contrast, forged flanges are not only reliable but also able to withstand more pressure. Forged parts come with around 37% fatigue strength. It is higher than other types, and it means that they last longer. Therefore, it is best to invest in high-strength that forge products as it is usually better for long-term investments using the high-pressure application.


If you are not fully aware of varied types and applications before buying flanges, the above facts will help you understand and make the right choice for your industrial project. We hope that with the help of this guide, you will be able to identify the key things before purchasing flanges. To learn more about flange basics, visit

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