Steel
wire ropes are likely to deteriorate due to bend fatigue when subjected
to bending around a sheave or drum. The rate of deterioration will be
influenced by the number of sheaves in the system, the diameter of the
sheaves and drum, and the loading conditions.
When selecting a wire rope for an application where bending fatigue is
a principal cause of deterioration it is important to select a rope containing
small wires e.g. 6x36 WS (14/7 & 7/7/1) as opposed to a 6x19 S (9/9/1).
Additional resistance to fatigue leading to real cost savings can be achieved
by selecting a “Dyform” wire rope.
The smooth surface of the “Dyform” product provides improved rope to sheave contact leading to reduced wear on both rope and sheave . Increased cross-sectional steel area and improved inter - wire contact ensures that the rope will operate with lower internal stress levels resulting in longer bending fatigue life and lower costs.
This graph illustrates a “doubling” in life when moving from Blue Strand 6x36 to Endurance Dyform 6. This same relationship can be found when moving from any construction into an equivalent Dyform construction e.g. 18x7 to Endurance Dyform 18 or 35x7 to Endurance Dyform 34LR.