Which welding technique uses a non-consumable electrode?

The welding technique that utilizes a non-consumable electrode is TIG welding. In TIG (Tungsten Inert Gas) welding, a tungsten electrode is employed to create the arc necessary for welding. This tungsten electrode does not melt or become part of the weld pool; instead, it provides the necessary heat to fuse the base materials together. The process also involves the use of a shielding gas, typically argon, to protect the weld area from atmospheric contamination.

This non-consumable electrode approach allows for greater precision and control over the welding process, making it especially beneficial for thin materials and applications where clean, high-quality welds are required. The other welding techniques listed in the question involve consumable electrodes, which contribute material to the weld itself, leading to different applications and characteristics in the welding process.