Why is DC+ polarity not commonly used in GTAW applications?

Why is DC+ polarity not commonly used in GTAW applications?

• A. It causes excessive spatter
• B. It cannot penetrate thick materials
• C. Overheating of tungsten can occur
• D. It produces a weaker arc

Answer: (C)

In Gas Tungsten Arc Welding (GTAW), DC+ polarity, which means the current flows from the electrode to the workpiece, can lead to overheating of the tungsten electrode. This occurs because the positive polarity provides more heat concentration at the workpiece rather than at the electrode. As a result, the tungsten does not have enough heat dissipation, which can lead to it reaching its melting point more quickly than it would under other polarities. Under DC+ polarity, the welding arc primarily establishes at the workpiece, which can cause the tungsten to overheat and potentially erode. This overheating can affect the stability and performance of the arc, and the integrity of the weld can suffer as a consequence. Therefore, avoiding DC+ in GTAW helps maintain the longevity of the tungsten electrode and ensures a more stable arc, making this configuration less favorable for applications requiring precision and control.

In Gas Tungsten Arc Welding (GTAW), DC+ polarity, which means the current flows from the electrode to the workpiece, can lead to overheating of the tungsten electrode. This occurs because the positive polarity provides more heat concentration at the workpiece rather than at the electrode. As a result, the tungsten does not have enough heat dissipation, which can lead to it reaching its melting point more quickly than it would under other polarities.

Under DC+ polarity, the welding arc primarily establishes at the workpiece, which can cause the tungsten to overheat and potentially erode. This overheating can affect the stability and performance of the arc, and the integrity of the weld can suffer as a consequence. Therefore, avoiding DC+ in GTAW helps maintain the longevity of the tungsten electrode and ensures a more stable arc, making this configuration less favorable for applications requiring precision and control.