API 571 Mechanical Fatigue

  1. Mechanical fatigue is caused by:
    cyclic stresses occurring over a long period of time
  2. What materials are affected by Mechanical fatigue?
    All materials - the number of cycles necessary to cause failure vary per material.
  3. Fatigue will NOT occur in carbon steel if stresses are below what?
    Endurance limit
  4. What conditions contribute to Mechanical fatigue?
    • Temperature - Not a factor
    • Steel Properties - Dirty Steel
    • Grain Structure - Coarse-grain
    • Surface Condition - Notches
    • Process pH - Not a factor
  5. The endurance limit is usually about:
    40-50% of a materials ultimate tensile strength
  6. What material does not have an endurance limit?
    Stainless steel
  7. Mechanical fatigue can cause cracks that initiate from the surface and often form what?
    clam shell appearance
  8. The best defense against mechanical fatigue is a:
    Good design that minimizes stress concentrations
  9. Inspecting for high-cycle fatigue can be difficult since:
    once the crack begins, only a few cycles are needed for the crack to lead to failure.
Card Set
API 571 Mechanical Fatigue
API 571 Mechanical Fatigue