Slip On Flange

As one of the most cost-effective and widely used flange types in industrial piping systems worldwide, SO Flanges (Slip On Flanges) are characterized by their simple structure—they feature a flat face or raised face and a short hub, allowing the pipe to slip through the flange bore before welding, which simplifies installation and reduces labor costs.

Both standard slip on flanges and hubbed slip on flanges provide reliable connection performance, making them suitable for a wide range of applications, including general industrial piping, water supply and drainage systems, oil and gas pipelines, and chemical processing plants. They are particularly ideal for low to medium pressure environments, as well as applications where frequent disassembly and maintenance are not required.

The bore of a slip on flange is slightly larger than the outer diameter (OD) of the connected pipe, enabling the pipe to slide smoothly into the flange. This design allows for easy alignment during installation, ensuring a tight and secure fit after welding. It is important to select the correct flange size and pipe diameter when purchasing slip on flanges to avoid misalignment and ensure optimal performance.

Slip on flanges are attached to pipes via fillet welding on both the inner and outer sides of the flange hub. This double-welded connection enhances the strength and sealing performance of the joint, preventing fluid leakage. For applications with higher pressure or more demanding operating conditions, the welds can be inspected using non-destructive testing methods such as ultrasonic testing (UT) to ensure structural integrity.

Raised face (RF) and flat face (FF) configurations are available for slip on flanges, with raised face being the preferred choice for most industrial applications due to its better sealing performance when paired with gaskets. Slip on flanges are also available in various pressure classes, from 150# to 2500#, to meet the diverse needs of different piping systems. Standard bore sizes are commonly used, while custom bore sizes can be provided for special applications.

We offer a complete range of slip on flanges, manufactured from high-quality materials such as ASTM A105, 20#, Q235, 16Mn, ASTM A350 LF1, LF2 CL1/CL2, LF3 CL1/CL2, stainless steel (304, 316, 316L), duplex and super duplex steels, and nickel alloys. Whether you need standard flanges or custom-made products, please feel free to contact us—we are committed to providing high-quality flange solutions that meet your specific requirements!