7 Things You Did Not Know About Carbon Steel Flanges

Carbon steel flanges are important in the oil and gas industry and other heavy-duty applications. They serve as a bridge between pipes, valves, and other equipment and play a significant role in maintaining the integrity of a system. Carbon steel flanges have been used for decades and have undergone several changes to meet the evolving demands of different industries. But there are some lesser-known facts about carbon steel flanges. This blog will explore seven things about carbon steel flanges that you probably still need to learn.

What is Carbon Steel Flanges?

Carbon Steel Flanges are pipe connections used to connect sections of pipes. Typically, the flange is round and fits over the end of one pipe, while the other side is bolted to another length of pipe or a valve. The available types include Round bars, Forged Bars, Hollow Bars, and Hex Bars. Carbon Steel Flanges come in different sizes and pressure ratings for various applications such as oil refineries, chemical plants and power plants.

7 Things You Did Not Know About Carbon Steel Flanges

Carbon Steel Flanges and Corrosion

Carbon steel flanges are prone to rust and corrosion if not properly treated. Flanges exposed to moisture and humidity are more susceptible to rust than others. However, galvanisation can protect carbon steel flanges against rust and corrosion. This process involves coating the surface of the flange with zinc to prevent rust formation. Galvanization also increases the lifespan of carbon steel flanges and makes them more suitable for heavy-duty applications.

Carbon Steel Flanges and Pressure Rating

The pressure rating of carbon steel flanges varies depending on the thickness of the flange and the material used. Carbon steel flanges are rated based on their ANSI class, which ranges from 150 to 2500. The higher the class, the greater the pressure the carbon steel flange can withstand. Choosing the right pressure rating for a specific application is important to prevent equipment failure or catastrophic accidents.

Carbon Steel Flanges and Dimensions

Carbon steel flanges come in different sizes, shapes, and dimensions. The most common shape is the round flange, a flat or raised face. Carbon steel flanges also have a variety of bolt-hole patterns, such as square, oval, or triangular patterns. It is important to check a flange’s dimensions and bolt-hole pattern before ordering to ensure a proper fit.

Carbon Steel Flanges and Material Properties

Carbon steel flanges are made from different grades of carbon steel, each with varying material properties. The most common Carbon steel flanges grades used to manufacture flanges are ASTM A105 and ASTM A350 LF2. ASTM A105 is a low carbon steel grade often used for general-purpose applications, while the ASTM A350 LF2 is a low alloy steel with higher tensile strength and better toughness.

Carbon Steel Flanges and Welding

Carbon steel flanges can be welded to pipes using different welding techniques, including arc welding, TIG welding, and MIG welding. Using the right welding technique for a specific application is important to ensure a strong and reliable joint. Improper welding can weaken the flange and cause leaks or equipment failure.

Carbon Steel Flanges and Temperature

Carbon steel flanges can withstand a wide range of temperatures depending on the material grade used and the intended application. ASTM A105 carbon steel flanges can withstand temperatures up to 1000°F, while the ASTM A350 LF2 can withstand temperatures up to 800°F. Selecting the right material grade and pressure rating for a specific application based on the expected temperature range is important.

Carbon Steel Flanges and Environmental Impact

Carbon steel flanges have a significant environmental impact. Manufacturing carbon steel flanges involves the release of greenhouse gases and other pollutants that contribute to climate change. However, carbon steel flanges can be recycled and reused, reducing the environmental impact of their manufacturing. It is important to consider the environmental impact of carbon steel flanges when choosing between different materials for a specific application.


Carbon steel flanges are an essential component in various industries, but there are still things we still need to learn about them. This blog explored seven things about carbon steel flanges that you probably still need to learn. From galvanization and pressure rating to material properties and environmental impact, carbon steel flanges have many factors to consider when selecting them for an application. Choosing the right carbon steel flange for a specific application is essential to ensure proper equipment functionality and reliability.