TM5-3810-305-10 11. Peening: Continuous pounding is one of the causes of peening. The rope strikes against an object such as some structural part of the machine, or it beats against a roller, or it hits itself. Often, this can be avoided by placing protectors between the rope and the object it is striking. Another common cause of peen- ing is continuous passage, under high ten- sion, over a sheave or drum. Where peening action cannot be controlled, it is necessary to have more frequent inspections and to be ready for earlier rope replacement. The external appearance of two ropes are il- lustrated, one of which has been abraded and the other peened (Figure 4-42). Also shown are the cross-section of both wires in these conditions. Note that a crack has formed as a result of heavy peening. 12. Scrubbing: Scrubbing refers to the displace- ment of wires and strands as a result of rubbing around or against an object. This, in turn, causes wear and displacement of wires and strands along one side of the rope. Corrective measures should be taken as soon as this condition is observed. 13, Fatigue Failure: Wires that break with square ends and show little surface wear have usually failed as a result of fatigue. Such failures can occur on the crown of the strands, or in the valleys between the strands where  adjacent  strand  contact  exists.  In almost all cases, these failures are related to bending stresses or vibration. If the diameter of the sheaves, rollers or drum cannot be increased, a more flexible rope should be used. But, if the rope in use is already of maximum flexibility, the only remaining course that will help prolong its service life is to move the rope through the system by cutting off the dead end. By moving the rope through the system, the fatigued sections are moved to less fatiguing areas of the reeving. This technique is most frequently used in rotary drilling. 14. Broken Wires: The number of broken wires on the outside of a wire rope are considered an index of its general condition, and whether or not it must be considered for replacement. Frequent inspection will help determine the elapsed  time  between  breaks.  Ropes  should be replaced as soon as the wire breakage reaches the numbers given in Table 7. Such action must be taken without regard to the type of fracture. On occasion, a single wire will break shortly after  installation.  However,  if  no  other  wires Table 7.  When to Replace Wire Rope. Based on Number of Broken Wires Number Broken Wires Number Broken Wires In  Running  Ropes In  Standing  Ropes ANSI In One In One In One At End No. Equipment Rope Lay Strand   Rope   Lay Connection B30.5 Crawler. Locomotive & Truck Cranes 6 3 3 2 4-48