Final answer:
A fillet weld must be repaired if it contains imperfections or discontinuities such as excessive concavity or convexity, undercut, lack of fusion, porosity, or cracks which compromise its integrity, quality, or strength.
Step-by-step explanation:
A fillet weld must be repaired if its profile has imperfections or discontinuities that compromise the weld's integrity, quality, or strength. According to welding standards, common reasons for weld repair include excessive concavity or convexity, undercutting, lack of fusion, porosity, or cracks.
Moreover, the leg length or throat thickness might not meet the specified requirements, necessitating a repair to ensure the structural performance of the welded joint.