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 tip of the torch holds the constricting nozzle with an orifice for the arc and plasma to pass thru. The arc is constricted into a focused plasma column of ionizing gas that is able to carry much more energy than an ordinary welding arc. As compared to an oxyacetylene flame which is around 6000F, A plasma arc is upwards of 20,000F. This intense focused heat allows for quicker cuts and less distortion.