Bearing metal that flexes during use is the cause of __________ in a bearing.

• A. Ultimate fatigue
• B. Creep
• C. Overload
• D. Wear particles

Answer: (A)

Cyclic loading causing metal fatigue leads to bearing failure. When a bearing is in service, the load isn’t constant; it flexes with each rotation, producing alternating bending stresses. Repeated stress—even if each cycle is below the strength of the metal—causes tiny cracks to form at flaws on the surface and then grow with every cycle. After many cycles, those cracks coalesce and the bearing material fractures, a failure we call fatigue. This explains why bearing metal that flexes during use is associated with fatigue failure.

Creep, overload, and wear particles describe different failure modes: creep is slow deformation under a constant high temperature and stress, overload is failure from a single excessive load, and wear particles come from surface material removal during sliding.