Quality Assurance in Welding: Module 7

Objective:

  Know about imperfections in welds.

Scope:

• Origin of imperfections: parent metal; welding process; welder; joint preparation
• Survey of specific weld imperfections and their cause
• Influence of weld imperfections on product performance
• Influence of the weld geometry on the fatigue life of the product

Expected results:

• Identify and describe the cause of: gas pores, incomplete penetration, lack of fusion and cracks (see also the specific modules "S" on welding processes .

List of Contents

1. Visual Inspection (VT)
2. Defects/imperfections in welds porosity
3. Identification
4. Cause and prevention
5. Distributed porosity and surface pores
6. Fig. 1. Uniformly distributed porosity
7. Fig. 2. Surface breaking pores (T fillet weld in primed plate)
8. Prevention
9. Wormholes
10. Elongated pores or wormholes
11. Prevention
12. Crater pipe
13. Prevention
14. Porosity susceptibility of materials
15. Principal gases causing porosity and recommended cleaning methods