I. Matching Errors
1. Strength Mismatch: Pairing a low-strength nut with a high-strength bolt can easily cause the nut's threads to strip and break under load, leading to structural failure.
2. Thread Mismatch: Forcing nuts and bolts with different pitches or standards to fit together directly causes thread stripping and seizing.
3. Material Mismatch: Direct contact between different metals can lead to electrochemical corrosion in humid environments, accelerating rust at the connection point.
II. Operational Errors
1. Torque Uncontrolled: Using an electric impact wrench to tighten directly, with torque far exceeding the nut's capacity, can cause the nut to crack and fail.
2. Incorrect Tightening Sequence: Tightening multiple nuts sequentially on one side results in uneven stress on the workpiece, causing deformation and significantly reducing the fit of the connection.
3. Failure to Clean Impurities: Residual iron filings and oil in the threaded hole cause uneven stress on the nut during tightening, resulting in insufficient preload.
4. Improper Wrench Use: Using a worn-out, rounded Allen wrench causes the nut's hexagonal head to become rounded, making subsequent disassembly impossible.
III. Misconceptions
1. Thick Nut Misconception: The misconception that thicker nuts improve connection reliability. In reality, excessively thick nuts result in uneven load distribution across the threads, making them more prone to loosening.
2. Reuse Misconception: Nuts with severely worn threads after repeated disassembly and assembly continue to be used, failing to guarantee proper tightening force and posing a safety hazard.
3. Multiple Washers on One Nut Misconception: Overlapping too many washers under the nut results in insufficient effective thread engagement, significantly reducing connection strength.
IV. Scenario-Inappropriate Misconceptions
1. License Plate Installation Violation: Improperly securing the nut during license plate installation leads to loosening or misalignment, resulting in fines and points deductions for driving on the road.
2. Lack of Protection in Harsh Environments: Using nuts made of appropriate anti-corrosion materials in humid or salt-spray environments, without proper sealing protection, leads to severe corrosion within a short period.
