Gas tungsten arc welding (TIG/GTAW) — electrode type In tungsten-inert gas arc welding, the electrode used is best described as:

Introduction / Context:
TIG (GTAW) is a high-quality welding process widely used for stainless steels, aluminum, and titanium. The nature of the electrode directly influences filler addition, shielding, and weld cleanliness.

Given Data / Assumptions:

• The process uses a tungsten electrode and inert gas (argon/helium) shielding.
• Filler metal may be added separately as a rod or omitted for autogenous welds.
• No flux is used in standard TIG welding.

Concept / Approach:
A sintered or alloyed tungsten electrode (e.g., pure W, thoriated, ceriated, lanthanated) establishes the arc but does not intentionally melt into the weld. It is therefore classified as non-consumable. The shielding gas protects the arc and molten pool from atmospheric contamination.

Step-by-Step Solution:
Identify process: tungsten electrode + inert gas.Electrode purpose: carry arc, maintain tip; it is not a filler source.Hence, select 'Non-consumable'.

Verification / Alternative check:
Process diagrams show separate filler rod when required; the tungsten electrode length is maintained by periodic grinding, not by continuous melting as in consumable-electrode processes.

Why Other Options Are Wrong:
Consumable and flux-coated options describe SMAW/MIG-like processes; self-shielded consumables apply to flux-cored arc welding.

Common Pitfalls:
Contaminating the tungsten by dipping into the pool; using wrong polarity on aluminum (needs AC with proper balance) or DCEN for steels; inadequate gas shielding leading to porosity.

Final Answer:
Non-consumable