text: Sustained load cracking, or SLC, is a metallurgical phenomenon that occasionally develops in pressure vessels and structural components under stress for sustained periods of time.
  It is particularly noted in aluminium pressure vessels such as diving cylinders.
  Sustained load cracking is not a manufacturing defect; it is a phenomenon associated with certain alloys and service conditions:
  *6351 aluminum alloy
  *Overstressing due to excessive filling pressure
  *Abuse and mechanical damage