11 Common Welding Defects and How to Prevent Them

Inclusions

Undercutting

Poor Joint Penetration

Burn-Through

Overlap

Craters

Spatter

Incomplete Fusion

Arc Strike Discontinuities

Excessive Reinforcement

Fortunately, all of these defects are simple to prevent from occurring if you follow the guidelines presented in this article. A major key to avoiding defects in welding is selecting the right equipment. Hopefully, this article can help point you in the right direction for welding equipment selection.
Table of Contents

• 
  Discontinuities vs. Defects
  
• 
  1. Porosity
  
• 
  2. Inclusions
  
• 
  3. Undercutting
  
• 
  4. Poor Joint Penetration
  
• 
  5. Burn-Through
  
• 
  6. Overlap
  
• 
  7. Craters
  
• 
  8. Spatter
  
• 
  9. Incomplete Fusion
  
• 
  10. Localized Discontinuities from Arc Strike
  
• 
  11. Excessive Reinforcement
  

Discontinuities vs. Defects
The term “discontinuities” and the term “defect” are not to be confused when welding. All defects are discontinuities, but not all discontinuities are defects. A discontinuity is a disruption in the weld bead that may not necessarily compromise the structural integrity of the weld.
Welding codes do provide a little room for error, as long as the integrity of the weld is not being compromised. However, discontinuities certainly have the potential to become defects. At the very least, it is important to understand how discontinuities can escalate into defects. Most welding defects are easily preventable. You will find the many of them can be prevented if the operator follows the right technique.