Which factor is a prime cause of burn-through in GTAW?

Which factor is a prime cause of burn-through in GTAW?

• A. electrode contamination
• B. excessive travel speeds
• C. high welding currents
• D. excessive filler metal

Answer: (C)

Burn-through happens when heat input to the base metal is more than it can safely absorb, causing the metal to melt through the joint. In GTAW, heat input is mainly controlled by the welding current: higher current dramatically increases the arc heat at the weld area, which raises the risk of burning through especially on thinner materials or tight joints. That direct link between current and heat makes high welding currents the prime cause of burn-through. Electrode contamination can cause arc instability and porosity, but it doesn’t drive burn-through. Traveling faster reduces heat input, which lowers burn-through risk, while using more filler metal changes weld size rather than the fundamental tendency to burn through.

Burn-through happens when heat input to the base metal is more than it can safely absorb, causing the metal to melt through the joint. In GTAW, heat input is mainly controlled by the welding current: higher current dramatically increases the arc heat at the weld area, which raises the risk of burning through especially on thinner materials or tight joints. That direct link between current and heat makes high welding currents the prime cause of burn-through. Electrode contamination can cause arc instability and porosity, but it doesn’t drive burn-through. Traveling faster reduces heat input, which lowers burn-through risk, while using more filler metal changes weld size rather than the fundamental tendency to burn through.