Recognize different causes of a damaged threaded joint
- Thread gallingThis term
Raised and torn material indicates adhesive wear. Review material pairing, friction, cleanliness and permitted lubrication.
- Thread seizure
The joint no longer moves freely. Galling, corrosion or deformation may be responsible; seizure names the condition, not one cause.
- Cross-threading
The mating part starts at the wrong angle or path. Extra tightening force must not be used to overcome a damaged start.
- Thread stripping
Sheared ridges remove load-carrying engagement. Review material strength, effective engagement and installation loading.
- Self-loosening
Relative movement or settlement can reduce clamp load. Initial tightening torque alone does not prove service stability.
Adhesive wear, seizure, a misaligned start, sheared ridges and loosening are distinct problems. Increased torque can worsen several of these conditions.
Exaggerated failure sketches without load values. Investigate the cause and replace or repair components through the approved assembly procedure.