Cause Analysis：

1. The tungsten electrode has pores; 2. The sharpening point is not concentric; 3. There is a problem with the welding torch angle.

solution：

1. The tungsten electrode is not straight, it can be straightened by hand, and you can't find the manufacturer to replace it; 2. Use a sharpened tungsten electrode with high concentricity, and re-sharpened the tip in time after the mushroom head is generated during the welding process of the tungsten electrode tip; 3. Check the welding Adjust the torch angle in time.