| Defect | Visual appearance | |--------|-------------------| | Undercut | Groove along weld toe | | Porosity | Round or elongated cavities | | Slag inclusion | Irregular dark lines/patches | | Lack of fusion | Flat, unbonded area | | Cracks (HIC, crater, longitudinal) | Fine, sharp line | | Overlap | Rolled-over metal at toe | | Incomplete penetration | Root gap not filled |
Candidates are not required to have previous qualifications to take the course, but they must meet specific experience requirements to be eligible for the examination. TWI recommends the following: cswip 3.1
