Flash welding is a process of resistance welding that involves heating and melting the end surfaces of two metal workpieces to be joined. There are several synonyms for flash welding, including percussion welding, upset welding, and forge welding. Percussion welding is a type of flash welding that uses striking force to heat and bond the metal pieces together. Upset welding is similar to flash welding but involves heating and softening the metal pieces before forcing them together. Forge welding is a manual welding process that uses a hammer and anvil to create a strong bond between the metal workpieces. No matter what synonym is used, flash welding produces a strong and durable joint that is commonly used in several industrial applications.