Welding is a process used to join two or more metal pieces by heating them to a suitable temperature with or without pressure and filler metal. During welding, improper techniques, poor materials, or incorrect parameters may lead to welding defects. These defects reduce the strength, durability, and reliability of welded joints.
1. Porosity
Porosity is the presence of small gas pockets or cavities trapped inside the weld metal during solidification.
| Causes | Remedies |
|---|---|
| 1. Moisture in electrode or flux 2. Dirty or oily base metal 3. Improper shielding gas flow 4. Too long arc length 5. High welding speed | 1. Clean the base metal properly before welding 2. Use dry electrodes and flux 3. Maintain correct shielding gas flow 4. Use proper arc length 5. Reduce welding speed if necessary |
2. Undercut
Undercut is a groove formed at the edge of the weld that reduces the thickness of the base metal.
| Causes | Remedies |
|---|---|
| 1. Excessive welding current 2. Too long arc length 3. High welding speed 4. Incorrect electrode angle | 1. Reduce welding current 2. Maintain proper arc length 3. Reduce welding speed 4. Maintain correct electrode position |
3. Slag Inclusion
Slag inclusion is the entrapment of slag particles within the weld metal or between weld layers.
| Causes | Remedies |
|---|---|
| 1. Inadequate cleaning between weld passes 2. Incorrect welding angle 3. Low welding current 4. Narrow groove angle | 1. Remove slag thoroughly between passes 2. Maintain proper electrode angle 3. Increase welding current appropriately 4. Provide proper groove design |