Posted by Robert Hernandez on Sep 6th 2026
| Term | Definition |
|---|---|
| Tack weld | A small weld used to temporarily hold components together until final welding. |
| Tack welding tip | A pointed tip for a plastic welding torch used to tack weld plastic weldments. |
| Tail | The “V” shape drawn at one end of a welding symbol where special notes are placed. |
| Tank | A thin-walled container for liquids or gases. Tank walls are thinner than pressurized gas cylinders. |
| Tap | One of several electrical contacts on a resistance welding machine. Each tap provides a different amperage range. |
| Teach pendant | An electronic control used to program a robot to perform a sequence of actions stored in computer memory. |
| Teflon liner | Smooth tubing used inside a cable to improve electrode wire feed in MIG (GMAW) welding. Commonly used for aluminum wire. |
| Tempering | A heat treating process in which metal is heated below its melting point to reduce hardness and increase toughness. |
| Tensile strength | The maximum pull stress (in psi) a material can withstand before failure. |
| Tensile test | A test in which a sample is pulled until failure to measure its ability to withstand pulling forces. |
| Terminals | The physical connectors on a welding machine for attaching the electrode and work leads. |
| Thermal radiation | Heat rays given off by a welding arc or heated base metal. |
| Thermal spraying | A process in which a material is heated and sprayed onto a surface. |
| Thoria | An alloying element used in TIG (GTAW) tungsten electrodes to improve arc starting. |
| Three-phase circuit | An electrical circuit delivering three cycles within 360 degrees, each 120 degrees apart. |
| TIG Welding (GTAW) |
A welding process that joins metals using a non-consumable tungsten electrode and shielding gas. |
| T-joint | A joint formed by placing one metal at 90 degrees to another. |
| Toe of weld | The junction between the weld face and the base metal. |
| Torch | A device used in TIG welding to hold the electrode, transfer current, and direct shielding gas. |
| Touch start | A TIG starting method where the tungsten touches the workpiece and establishes an arc when lifted. |
| Toughness | The ability of a material to withstand stress without breaking. |
| Trail cup | A special TIG gas cup used to provide additional shielding gas coverage on non-ferrous or oxidizing metals. |
| Transferred arc | An arc established between the electrode and the workpiece. |
| Transformer | An electrical device used to increase or decrease voltage. |
| Tungsten | A metallic element with a very high melting point used in TIG electrodes. |
| Tungsten grinder | A device used to grind the proper geometry onto a TIG tungsten electrode for improved arc performance. |
| Tungsten inclusions | A weld defect caused by tungsten particles contaminating the weld. |
| Two-stage regulator | A regulator that reduces cylinder pressure in two stages for more stable output. |
