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What Are Slip-On Flanges?


Slip-on (SO) flanges are a type of flange that has a flat face on the sealing surface and are typically used in low-pressure applications. They are called “slip-on” because they can be easily slipped onto the end of a pipe or fitting and then welded in place. They also have a bored-out inner diameter that matches the pipe’s outer diameter, allowing for a smooth flow of fluids or gases.

This article will explore the fundamentals of these flanges, including their working principles, advantages, and various types available.

How Slip-On Flanges Work

SO flanges provide a secure and leak-resistant connection between pipes or fittings in a piping system. The process begins by slipping the flange onto the end of the line, ensuring the flange’s inner diameter matches the pipe’s outer diameter. This allows for a smooth transition and maintains a consistent flow path.

Once the component is positioned correctly, it is then welded to the pipe. The welding creates a strong bond between the flange and the line, ensuring a reliable and durable connection. Moreover, the flange’s flat face provides a sealing surface easily aligned with gaskets or rings to prevent leakage.

Advantages of Utilizing Slip-On Flanges

SO flanges offer the following advantages, making them a popular choice in numerous piping systems across different industries:

Ease of Installation

The slip-on design enables effortless mounting to the end of a pipe or fitting without intricate alignment procedures. This saves time and effort during installation, especially when many flanges are involved. They can also be adjusted slightly after sliding onto the pipe, simplifying proper alignment between pipes or fittings.

Cost-Effective Solution

The design of SO flanges is relatively simple, resulting in less manufacturing complexity and lower production costs thanĀ other types. This affordability makes them ideal, especially for projects with budget constraints. Furthermore, the reduced welding material results in cost savings on consumables like welding rods or wires.

Availability and Compatibility

They are conveniently accessible in various sizes, materials, and pressure ratings, simplifying the search for the ideal flange that meets specific needs. Moreover, they exhibit compatibility with diverse types of pipes and fittings, allowing for versatility in their usage. This compatibility extends to various materials including carbon, steel, and alloy materials enabling seamless integration with different systems.

Space Efficiency

SO flanges have a compact and streamlined design. They have a flat face, unlike weld neck or socket weld flanges with protruding necks or socket extensions. This design minimizes the overall footprint of the flange, allowing for more efficient use of space within the piping system. They also have a shorter length compared to other types.

Types of Slip-On Flanges and Their Applications

SO flanges are available in two main types, each designed to cater to specific requirements and applications within piping systems:

Standard Slip-On Flanges

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Standard or raised-face SO flanges have a raised face on the sealing surface. This feature provides a platform for the gasket, ensuring a reliable seal between the flange and the adjoining pipe or fitting. As a result, they are highly suitable for low-pressure applications where the bolt-tightening force can compress the gasket adequately to prevent leakage.

Lap Joint Slip-On Flanges

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Lap joint SO flanges have a flat face with a separate backing flange. The backing flange slides over the pipe end and aligns with the lap joint stub end, which is then attached to the pipe. This design allows for rotational movement, providing flexibility in alignment during installation or maintenance. They are commonly used in systems requiring frequent dismantling, thermal expansion, or contraction applications.

Trust Coastal Flange for Industry-Leading Flanges!

Coastal Flange offers an extensive range of slip-on pipe flanges, catering to various steel material grades such as carbon, stainless, and alloy! With a well-stocked inventory, we ensure quick availability, allowing you to obtain the required flanges without delays. Our efficient shipping processes also enable swift and reliable delivery, ensuring your project stays on track and meets its deadlines.

Contact us to learn more about our products, or request a quote now!

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