Welding

The oldest type of welding is forge welding, a process that dates to 2,000 B.C. Forge welding is a pressure-heat procedure used by blacksmiths and artisans to form metal into specific shapes, and to join metals such as copper and bronze together. Toward the beginning of the twentieth century, several new welding techniques were developed. The discovery of acetylene gas in 1836 by Edmund Davy led to oxyacetylene welding. Resistance welding was invented in 1877 by the British-born American electrical engineer Elihu Thomson (1853-1937). The electric arc, discovered by Sir Humphry Davy, was first used for welding by Auguste de Meritens in 1881. In the United States, C. L. Coffin received a patent for a bare metal electrode arc welding process in 1892. As the arc metal welding process was developed and improved, welding replaced riveted joints as a method of joining pieces of metal. In 1918, the first allwelded ship was launched, and in 1920 the first all welded building was constructed. Electric arc processes were used extensively during the post-World War I period. During World War II, inert gas welding was developed, and the gas shielded welding process was developed in 1948. Today, there are around 40 welding processes in use. Some newer welding processes include electron beam welding, laser beam welding, and solid state procedures such as friction and ultrasonic welding.