stainless steel tubing compression fittings

However, a butt weld fitting connection still has some disadvantages, including cost. The assembly that provides the best protection against vibration is a butt weld fitting. Since the metals are being permanently joined together, a well formed butt weld has the best resistance to vibration and fatigue. Though C&T fittings still provide a very solid connection when installed properly, some studies have found that for every three corrosion failures in the field, there is at least one vibration failure. And because the joints are threaded in uncontrolled environments, the fittings can become loose when subject to vibration. Special training is required to use the tools necessary for C&T fittings. They can also introduce metal shavings and cutting oil into the tubing ID, creating the requirement for an additional cleaning operation.

These processes are not always repeatable or consistent. However, like compression fittings, C&T fittings can be broken down and re-assembled for maintenance. All of this is typically performed in the field, significantly increasing the installation time and overall cost of using of C&T fittings. To ensure a tight seal, the tube ends must be precision formed with a fine surface finish and then threaded so the tubing is assembled firmly against the joint. They provide a solid and tight connection, where the tube is chamfered (“coned”) and countersunk into the fitting. compression) on one port to an alternative connection on another port, such as NPT or SAE thread, or male NPT to C&T and many other combinations.Ĭone and Thread (C&T) connections are sometimes used in very high pressure applications (up to 150,000 psi), but are most frequently used for “medium pressures” of up to 15,000 psi. Many are also available with the designated style (i.e. Sometimes they are used as reducing fittings for instance from a larger size connection such as 3/8 to a smaller, 1/4 tube. Each style of fitting is available with the specified size end connections and in different configurations, such as: Seamless stainless steel tubing provides a much more reliable performance than the use of longitudinally welded tubing.įor medium pressure applications (up to 15,000 psi) stainless tube fittings are specified by the tubing OD (outside diameter) i.e. They can all be used with medium pressure to high pressure tubing. The threads allow for positive lock and sealing the end face of tube to the fitting body. ⇒ Cone and Thread Fittings (C&T): Tube ends are coned (chamfered) and threaded. ⇒ Butt Weld Fittings: Permanently joins to the tube end by welding the surrounding metal at the tube end with the fitting. ⇒ Compression Fittings: Slide over the tube and use a ferrule design to coin and seal on the OD of the tube. They are differentiated by their end connections, each having its own advantages and disadvantages in specific applications. There are three primary styles of medium pressure tube fittings.

Stainless steel tubing compression fittings