1. Scratches, abrasions, and minor folds: Shallow mechanical damage can be locally removed using an angle grinder or belt sander to remove high points and crack sources, creating a smooth surface transition. The grinding depth should be controlled to not exceed 10% of the negative wall thickness deviation to avoid affecting pressure resistance.
2. External folds, hairline cracks, and shallow scabs: If the defects do not penetrate the substrate, the abnormal surface layer can be removed by turning or polishing. This is suitable for structural pipes with low precision requirements. After repair, eddy current testing or magnetic particle testing should be performed to confirm the absence of residual cracks.
3. Localized pits and rough surfaces: Point defects that do not penetrate the pipe wall and do not affect strength can be ground into a smooth transition shape. If used for decorative purposes, surface beautification treatment can be combined with sandblasting and coating.
4. Damaged thread end (rotten teeth) Minor damage at the beginning section can be repaired by retapping or rolling; for scenarios requiring high connection strength, it is recommended to use a wire thread insert to enhance the repair effect.
