TIG welding is a type of arc welding that uses a non-consumable tungsten electrode. Because the electrode does not add filler material to the weld, a separate welding rod is used if additional material is needed. TIG welding is used for welding regular steel, stainless steel, aluminum and other nonferrous metals, and can even be used on difficult alloys such as cast iron. TIG welding requires closer tolerances between the electrode and the work piece, and is considered to be more difficult than other types of welding.

TIG Welding Equipment

1. For TIG welding, the equipment used includes a TIG welding machine, TIG welding gun with tungsten electrode, shielding gas (usually argon), filler rod or filler wire (for automatic feeding guns) and personal protective equipment, including welding mask, gloves and coveralls.

 

TIG Welding Process

2. To create a basic weld using the TIG process, the welder holds the gun containing the electrode at a 10-degree angle from straight up and pointed in the direction the weld will go. This configuration is known as the "push" method. The push method maintains coverage of the shielding gas over the weld pool, and encourages the molten metal to move forward, resulting in a clean weld.

The welder begins the weld by moving the electrode around in a small circle, creating a pool of metal. Then he moves the electrode forward along the weld seam and adds filler material as needed until the end of the weld is reached. The forward motion of the electrode helps to move the molten material ahead to fill the weld.

 

Alternate TIG Techniques

3.  For thick welds where a lot of filler material is required to fill a weld, the hot wire technique is often used. This technique involves heating the welding wire before it reaches the weld to allow it to meld faster. All of the arc energy is used to heat the work piece and keep it hot. For thin sheet metals that could suffer warp or burn through because of the high heat of the TIG arc, the pulsed current process is used. In this process, the power supply pulses between two levels of voltage. The higher level of voltage melts the metal in the work piece, and the lower level provides a brief cooling period to prevent overheating.