AWS Welding Inspection and Testing Certification Practice Test

What leads to tungsten inclusions when using the GTAW process?

1. Inadequate shielding gas

2. High travel speed

3. Improper grinding of the electrode

4. Poor workpiece clamping

The correct answer is: Improper grinding of the electrode

Tungsten inclusions occur in the GTAW (Gas Tungsten Arc Welding) process primarily due to improper grinding of the tungsten electrode. The tungsten electrode needs to be ground to a specific point to ensure that it produces a stable arc. If the electrode is not ground correctly, it can lead to irregular arc stability and cause the tungsten to be transferred into the weld pool, which results in tungsten inclusions within the weld. When the electrode is adequately pointed and has the proper surface finish, it minimizes contamination and enhances the overall quality of the arc. However, if the grinding is uneven or the tip is not shaped correctly, it can create conditions that lead to the excessive erosion of tungsten. This can cause bits of the electrode to be swept into the molten weld puddle, leading to defects in the weld. The other factors, while they can influence the quality of the weld, do not directly cause tungsten inclusions in the same way that improper grinding does. Inadequate shielding gas may lead to porosity or other contamination but does not introduce tungsten. High travel speeds might lead to undercut or incomplete fusion but do not specifically lead to tungsten being included in the weld. Similarly, poor workpiece clamping can result in issues with alignment or stability