Let us understand the failure mechanisms due to fatigue caused by work hardening .Fatigue is a failure phenomenon associated with work-hardening of materials caused by fluctuating or repeated loads that result in increased brittleness and reduced service life of machine parts. Fatigue is characteristic of ductile materials but the final failure is rapid and characteristic of brittle fracture.
The time leading up to fatigue failure cannot be predicted exactly but the following conditions are known to result in work- hardening, leading to fatigue:
• a relatively large, fluctuating applied stress
• a sufficiently large number of stress cycles
Fracture failure due to fatigue often occurs at relatively low applied stress and well within specified design loads. The stress can be mechanical, thermal or both and can alternate between compression and
tension, or simply alternate between high and low values.The best ways to ensure a reasonable service life for parts subject to the above conditions is; to ensure that scratches and other surface imperfections are removed by polishing and, if possible, by heat treatment, which relieves internal strains.
The only reasonably reliable methods of checking the progress of fatigue are by visual, x-ray or ultra-sound examination for surface and other cracks of the parts likely to be subject to work- hardening.
The anxiety might be mechanical, warm or both and can exchange between machined parts layering and pressure, or essentially substitute between high and low qualities .
ReplyDeleteFatigue is a failure phenomenon associated with work-hardening of materials caused by fluctuating or repeated loads that result in increased brittleness and reduced machined parts service life. Fatigue is characteristic of ductile materials but the final failure is rapid and characteristic of brittle fracture.
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