Lisbon's Vasco da Gama Bridge is the longest in Europe, spanning a total distance of 10.7 miles. Taking three years to complete, the bridge opened for traffic in 1998 to celebrate the 500th anniversary of Vasco da Dama's discovery of the maritime route from Europe to India.
The arc temperature may be upto 20,000 K. Although TIG welding produces the highest quality welds, it is a slow and expensive process. Metal inert gas welding process (MIG) is economical with consumable electrode fed at a predetermined rate. Plasma arc welding (PAW) has made substantial progress in utilising the high heat energy of an ionised gas stream.
The most common types of welding include: Gas Metal Arc (GMAW). This common process, often referred to as MIG (Metal Inert Gas) welding, is carried out by automatically feeding a consumable metal electrode and shielding gas through the nozzle of a torch. In this process, the electrode is also the filler.