Verification of suitability for use of defective welded assemblies
Welded mechanical parts - Fatigue design of welded joints and harmfulness of flaws

The presence of a flat defect in or near a welded joint in a structure in service, the origin of which may be either a manufacturing defect that went unnoticed during the end-of-manufacturing NDT (lack of fusion: 401; or lack of penetration: 402 according to standard NF EN ISO 6520-1), or a defect generated by the operation of the structure (fatigue crack type 1012 according to standard NF EN ISO 6520-1), generally leads to a fitness for service analysis (ECA). This analysis makes it possible to determine the stability of the defect with regard to:

• abrupt propagation in a brittle and/or ductile manner;

• slow propagation under variable load.

As this last aspect has been discussed in §