Tungsten inert gas welding
Under the protection of inert gas, an arc welding method is used to melt the base metal and filler metal (if filler metal is used) by using the arc generated between the tungsten electrode and the workpiece, referred to as TIG welding. The TIG welding process is shown in the figure. The non molten tungsten electrode emits electrons to generate an arc. The filler wire is fed from one side. Under the action of arc heat, the filler metal and the workpiece melt together to form a weld. In order to prevent the tungsten electrode from melting and burning, the welding current should not be too high. Therefore, TIG welding is usually suitable for welding thin plates less than 4mm.
In general, direct current is used for TIG welding, but alternating current is used for welding aluminum, magnesium and their alloys.
