1. The surface of the workpiece is not clean.
2. Electrode surface is not flat or sticky with welding metal.
3 The welding specification is poorly adjusted.
4 Electrode indentation is too deep.
5. Cracking: The main cause of cracking is rapid cooling rate, which is a common defect in welding alloy steel, while welding mild steel is rare.
6. Loose and shrinkage.
Normal welded joint surface electrode indentation depth shall not exceed 20% of the thickness of a workpiece. The cause of excessively deep electrode indentation can be attributed to severe overheating of the welded joint, excessive injection, small diameter of the electrode surface, or excessively large gaps in the workpiece assembly. On the other hand, issues related to looseness and shrinkage arise from excessive electrode pressure or inadequate maintenance time.