Friction welding (FRW) is a solid-state welding process that generates heat through mechanical friction between workpieces in relative motion to one another, with the addition of a lateral force called "upset" to plastically displace and fuse the materials. Because no melting occurs, friction welding is not a fusion welding process, but a solid-state welding technique more like forge welding. Friction welding is used with metals and thermoplastics in a wide variety of aviation and automotive applications. ISO norm of friction welding is EN ISO 15620:2019 there is information about basic terms and definitions and table of weldability of metals and alloys. History Some applications and patents connected with friction welding were dated back to the turn of the 20th century and rotary friction welding is the oldest of this methods. W. Richter patented the method of linear friction welding (LFW) process in 1924 in England and 1929 in Germany, however, the description of the process was vague and H.Klopstock patented the same process in the USSR 1924. But first description and experiments related to rotary friction welding took place in the Soviet Union in 1956, machinist named A. J. Chdikov has realized scientific studies and suggested the use of this welding method as a commercial process. The process was introduced to the USA in 1960. The American companies Caterpillar Tractor Company (Caterpillar - CAT), Rockwell International, and American Manufacturing Foundry all developed machines for this process. Patents were also issued throughout Europe and the former Soviet Union. The first studies of friction welding in England were carried out by the Welding Institute in 1961. The USA with Caterpillar Inc. and MTI developed an inertia process in 1962. Europe with KUKA AG and Thompson launches rotary friction welding for industrial applications in 1966, developed a direct-drive process and in 1974 builds rRS6 the double spindle machine for heavy truck axles. Another method was invented and experimentally proven at The Welding Institute (TWI) in the UK and patented in 1991 Friction stir welding (FSW) process a solid-state joining process that uses a non-consumable tool to join two facing workpieces without melting the workpiece material. In 2008 KUKA AG developed the friction welding machine SRS 1000 with a forged force of 1000 tons. An improved modification of the standard friction welding is also Low Force Friction Welding, hybrid technology developed by EWI and Manufacturing Technology Inc. (MTI), "uses an external energy source to