Pulsed GTAW has which of the following effects?

• A. Reduction in Porosity
• B. Increased Porosity
• C. Wider Heat Affected Zone
• D. Increased Burn Through

Answer: (A)

Pulsed GTAW delivers a high peak current for short bursts while spending most of the cycle at a lower background current, which lowers the average heat input. This gives you tighter control of the weld pool and arc, and helps the shielding gas establish a stable, protective blanket during the idle times. Porosity forms when gas pockets get trapped as the metal solidifies; the more stable, shielded, and lower-heat conditions of pulsed welding reduce gas entrapment and contamination of the molten metal, so porosity tends to decrease. In contrast, wider heat-affected zones and burn-through come from higher or continuous heat input, which pulsing purposefully avoids.