Welder Red Seal · Question
A welder performing GTAW on stainless steel notices significant porosity and a rapidly eroding, discoloured tungsten electrode. What is the most likely cause?
Contamination of the inert shielding gas (e.g., argon) with oxygen or moisture from the atmosphere will cause rapid oxidation of both the molten weld pool (poro
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Question: A welder performing GTAW on stainless steel notices significant porosity and a rapidly eroding, discoloured tungsten electrode. What is the most likely cause?
Answer options:
- The amperage is set too low for the material thickness.
- The travel speed is excessively fast. ✅ There is a leak in the shielding gas line or the gas is contaminated.
- The welder is using a 2% thoriated tungsten instead of a pure tungsten.
Correct answer: There is a leak in the shielding gas line or the gas is contaminated.
Explanation: Contamination of the inert shielding gas (e.g., argon) with oxygen or moisture from the atmosphere will cause rapid oxidation of both the molten weld pool (porosity) and the hot tungsten electrode, leading to poor arc performance and defects.
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