Friction Welding (FRW) – Welding Processes used in Aeronautical Industry
In this process (Welding Processes used in Aeronautical Industry), joining of the metals is achieved through mechanical deformation. Since there is no melting, defects associated with melting-solidification phenomena are not present and unions as strong as the base material can be made. This process can join components with a relatively simple cross section. It is used for joining aluminum landing gear components. Linear friction (fretting) welding is used as an alternative for the manufacture and repair of high temperature alloy blocks for jet engines.
Friction Stir welding (FSW)
It is a solid-state process that joins metals through mechanical deformation. In this process, a cylindrical shouldered tool with a profiled a probe is rotated and slowly plunged into the joint line between two pieces of sheet or plate material which are butted together. This process can weld unweldable aluminum alloys such as the 2xxx and 7xxx series used in aircraft structures. The strength of the weld is 30%-50% than with arc welding
Flash Welding (FW) : Welding Processes used in Aeronautical Industry
FW is melting and joining process in which a butt joint is welded by flashing action of a short arc and application of pressure. It is capable of producing welds as strong as the base material.
This process can weld aluminum and temperature resistant alloys without especial surface preparation or shielding gas. It can join sections with complicated cross sections and it is used in the aeronautical industry to join rings for jet engines made out of temperature resistant alloys and extruded aluminum components for the landing gear.
Gas Metal Arc Welding (GMAW) or MIG welding
This process is one of the most popular welding processes in the world because its flexibility and low cost. It is not used extensively in the aeronautic industry. This process is the main welding process used for the construction of the fuel and oxidizer tanks for the Saturn V rocket.
One of the current applications of MIG is in the automatic welding of the vanes of the Patriot missile. This application benefits from the low cost of MIG while extreme reliability is not as important as in manned airplanes.
Gas Tungsten Arc Welding (GTAW) or TIG welding
GTAW can use a more intense heat source than GMAW. So, it can produce welds with less distortion at a similar cost. For most structural critical applications, this process cannot compete with other welding methods such as electron beam welding, laser beam welding or plasma arc welding.
TIG welding was used together. with MIG welding to weld 2014 and 2219 aluminum alloy in the fuel and oxidizer tanks in the Saturn V rocket.
Plasma Arc Welding (PAW)
PAW uses a constricted arc between a non-consumable electrode and the weld pool (transferred arc) or between electrode and constricting nozzle (non-transferred arc).
If the heat intensity of the plasma is high enough, this process can operate in a keyhole mode which is similar to the laser or electron beam welding although with smaller maximum penetration.
Laser Beam Welding (LBW)
This process together with electron beam welding can deliver the most concentrated heat sources for welding with the advantages of higher accuracy, weld quality and smaller distortions. This process is used for welding and drilling of jet engine components made of heat resistant alloys such as Hastelloy X.
Laser-processed combustors, are used in the Pratt & Whitney jet engines. Laser beam welding will soon replace riveting in the joining of stringers to the skin plate in the Airbus 318 and 3XX aircraft 20.
Electron Beam Welding (EBW) : Welding Processes used in Aeronautical Industry
The high intensity of the electron beam generates welds with small heat affected zone. The characteristic makes this process especially suitable for welding titanium alloys which cannot be welded in an open atmosphere.
Titanium alloys are widely used in military aircraft because of its light weight, high strength and performance at elevated temperatures. The application of EBW to the welding of titanium components for military aircraft has been expanding constantly.
Critical titanium structural components are being EBW welded this way for the Eurofighter and Boeing’s F-22.
Diffusion Welding (DFW)
It is a solid-state welding process that produces a weld by the application of pressure at elevated temperature with no macroscopic deformation or relative motion of the pieces. The aeronautic industry is the major user of DFW.
Resistance welding in the aerospace industry is utilized to join parts made of certain metals that possess high strength and lightweight properties.