Loosening problem
Phenomenon: Bolts/nuts gradually loosen during use, resulting in connection failure.
Cause: Vibration, impact load, temperature change or insufficient preload.
Solution:
Use anti-loosening measures (spring washers, thread glue, double nuts, self-locking nuts, etc.).
Check and re-tighten regularly.
Corrosion and rust
Phenomenon: Surface rust, reduced strength, and difficult disassembly.
Cause: Humid environment, chemical media or materials are not corrosion-resistant.
Solution:
Choose corrosion-resistant materials such as stainless steel (such as 304/316), galvanized or Dacromet coating.
Apply anti-rust grease regularly.
Fracture or deformation
Phenomenon: The fastener breaks or the thread is damaged after being stressed.
Cause:
Overload or fatigue load (repeated stress).
Material defects (such as internal cracks).
Excessive preload during installation (exceeding yield strength).
Solution:
Select high-strength grades (such as 8.8 and 12.9 grade bolts).
Use a torque wrench to accurately control the preload.
Thread stripping
Phenomenon: The thread fit fails and cannot be tightened.
Cause:
Low thread processing accuracy.
Misalignment during installation (biased stress).
Solution:
Replace the thread pair or use a thread repair tool (such as a wire thread insert).
Ensure that the bolt is aligned with the hole axis during installation.
Thermal expansion problem
Phenomenon: Fasteners loosen or get stuck in high temperature environment.
Cause: Different thermal expansion coefficients of materials lead to stress changes.
Solution:
Use high temperature resistant materials (such as A286 stainless steel).
Reserve thermal expansion gap when designing.