Seamless stainless steel tubing is found throughout aircraft hydraulic systems. It can be bent to shape much more easily than steel piping, withstand higher pressures, and connect more securely with proper hose fittings. Because a hose is only as good as the connection, it is critical to use high quality tubing or hose and fittings to foster a reliable seal. This is why aerospace hydraulic fittings of AS9100C and Nadcap quality are used in a wide range of industries. Components that meet these rigid requirements are used by OEMs and maintenance crews in industries such as civil aviation, aerospace and defense, industrial, as well as in construction, manufacturing, and commercial equipment. This blog will explain aerospace fittings, their types, and important considerations to make.
Unlike steel pipe, segments of steel tubing are usually attached with either flared or flareless fittings. These are the two main types of fittings. Flared fittings provide significant design and performance advantages over pipe fittings and can be used in both thin- and medium-wall tubing. In a flared fitting, the tubing is flared in preparation to install and secure the seal. It is made up of a sleeve and a nut, with the nut fitted and tightened over the sleeve. The nut draws the sleeve and flared tubing securely into a cone shaped male fitting to facilitate a seal. The sleeve also serves as a support to alleviate vibration at the flare, distributing the energy over a wider area.
As tube, hose, and fitting installations are used in critical applications such as aircraft, military equipment, heavy machinery, cranes, earth-moving equipment, and many other industrial sectors, the appropriate connection and torque are pivotal. Metal-to-metal contact between the fitting and flare is necessary to provide a reliable seal. For this reason, you should never apply pipe compound or sealing tape to the faces of the fitting or flare. It is also important to ensure the assembly is in alignment before applying the designated torque to the fittings.
The other type of fitting, flareless fittings, are used in medium- to high-pressure applications. These comprise a nut, single or double ferrule, and the fitting body. The nut and ferrules slide over a tube with an outer diameter that matches the inner diameter of the receiving fitting. As the nut is tightened to the appropriate torque, the ferrule is compressed against the tube, providing a seal. This is why flareless fittings are also known as compression fittings. One type of flareless fitting is the Military Standard (MS) flareless fitting. MS fittings are used in high pressure hydraulic systems (greater than 3,000 psi) in areas that will experience rigorous vibration of inconsistent pressure.
Additionally, O-Ring Boss (ORB) fittings are a type of fitting used for leak-tight connections. These fittings are very popular among aerospace equipment manufacturers and typically consist of a 90 durometer nitrile o-ring. There are two types of o-ring boss fittings: SAE straight-thread parts and face seal parts. Regardless of what type of fitting or fluid system components you are in need of, ASAP NSN Hub can find what you are looking for and get it to you quickly.
At ASAP NSN Hub, owned and operated by ASAP Semiconductor, we can help you source all types of fittings and aerospace standard parts and deliver them with some of the industry’s best lead times. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, call us at +1-920-785-6790 or email us at sales@asapnsnhub.com. Our team of dedicated account managers is standing by and will reach out to you in 15 minutes or less.
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