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Threaded Flange

The threaded flange (also called "bolted flange") style uses threads to connect the flange to the pipe. The end of the pipe is externally threaded and the hole in the flange is internally threaded. Then screw the male threaded pipe into the female threaded flange.

Available in a wide range of sizes and pressure ratings, the threaded flange design is primarily used for small piping systems. H. ≤ 4 inches. Also, its use is usually limited to non-toxic, low-pressure, and low-temperature systems. Threaded flanges in sizes 1/2" to 2" are much more common than sizes 2" and up. For low pressure applications, threaded flanges use only flat and raised surfaces. Not suitable for high temperature applications as the thread profile is distorted and often leads to leakage.

A big advantage of threaded flanges is that they can be connected to pipes without welding. Forming joints without welding is a great advantage, and in some places and industries, for example, gas stations, hexane plants, warehouses with flammable liquids, hazardous areas (hazardous areas). Potential sources of ignition are eliminated when welding is not required. Another advantage is that bolted flange connections are quicker and easier to assemble and disassemble than welded flange connections.

Threaded flange is not suitable for thin wall tubing as it is difficult to thread thin wall tubing. In some cases, seal welds can be used to improve flange integrity and reduce the chance of leaks. Adding a seal weld improves the integrity of the flange, but makes the joint more difficult to assemble and disassemble (since the weld is a permanent joint).

Most engineering groups and associations limit the use of threaded flanges to a size range of ½ inch to 4 inches and pressure class 300 or less. Because no welding is used, threaded flanges are more prone to leaks than welded ones, and gaskets are more susceptible to damage when flange misalignment occurs. For these reasons, threaded flanges are not suitable for hazardous systems where leakage can have catastrophic consequences.

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