Linear Friction Welding


Linear Friction Welding (LFW) has been established since the 1980ies as a niche welding process, where the work pieces are pressed against each other and moved forward and backward by ± 3 mm with a reciprocating motion of approximately 50 Hz. 


The process is mainly used by the aerospace industry, for instance to make the titanium blisks (bladed discs) of the Eurofighter. Das Verfahren wird vor allem in der Luft- und Raumfahrtindustrie eingesetzt.

 


LinFric®-Linear Friction Welding Machines

We have developed a hydraulic linear friction welding machine within the European LinFric®-Project (www.linfric.com). Even steel can be welded with this machine, for instance to make wheel rims of off-road vehicles. The main applications are, however, in the production of stationary turbines and Jet engines als well as the manufacture of near-net-shape parts by the aerospace industry.

 

The concept has been developed and proven in a collaborative project with eight European partners. The experiences and contributions of the individual partners were exploited very effectively.

 

The benefits of the hydraulic LinFric® machines are based o the innovative way to generate the oszillating motion in comparison to mechanically driven machines, which use a complicated gear box. Their heart is a hydraulic oscillator, which vibrates at a frequency of 25-125 Hz, an amplitude of up to 3 mm at an oil flow of up to 950 l/min. The maximum forging forces is 200 kN (20 t) so that cross sections of upe to 2000 mm²  can be welded in steel. The hydraulic oscillator can provide both sinusoidal and non-sinusoidal motions, which is useful for some of the materials to be welded.[1]

    

AVIC Linear Friction Welding Machine

A similar hydraulic linear friction welding , designated LFW-20T, was test was developed and home-made at AVIC Manufacturing Technology Institute, Beijing, China. The machine can for instance be used at  3 mm amplitude, 50 Hz frequency and 15 t friction pressure for  The size of TC17 titanium alloy samples with 20 mm (Z) × 75 mm (Y) × 120 mm (X), where Y is the vibration direction, X is the direction of friction pressure, and  thus a friction surface of 20 mm (Z) × 75 mm (Y).[2]

AVIC'S 20 t linear friction welding machine LFW-20T

© Xiaohong Li  Jianchao He, Yajuan Ji, Tiancang Zhang and Yanhua Zhang, CC BY 4.0

    


Publications on Linear Friction Welding

  1. Friction Welding of Aero Engine Components. 10th World Conference on Titanium Ti-2003, Hamburg, Germany, 13-18 July 2003.

  2. Yanhua Zhang, Xiaohong Li (School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, China) Jianchao He, Yajuan Ji and  Tiancang Zhang (Aeronautical Key Laboratory for Welding and Joining Technologies, AVIC Manufacturing Technology Institute, Beijing, China): Study of the Microstructure and Fracture Toughness of TC17 Titanium Alloy Linear Friction Welding Joint. Metals 2019, 9(4), 430CC BY 4.0. Published: 11 April 2019.