Quality of steel wire ropes Resulting from calculation, rope design, material, manufacturing
Technical Meeting Experiences with Ropes – Lenzburg 2003
lt is well known that great differences in fatigue bending cycles (1: 15 and greater) may be achieved with the same rope construction (rope characteristics), tested on the same fatigue bending machine (application), with the same test parameters but manufactured by different rope manufacturers (VDI 2358). Field results also show big differences but here only under consistent working condition can the real rope quality be judged. Also, quite often other rope damages than fatigue, are the reason for the necessity to discard the rope. The reason must be "different" rope quality by different manufacturers. Why do we have these great differences? There are many influences relating to the rope design, core diameter relation (Müller/Greis, 1979), lay length and lay angle relation, contact angles, additionally, the type of core can be critical. lt seems that in 8 strand constructions a 6 strand core is not as sensitive as a 8x7+1x19 construction. This type of core shows more internal centre strand or core breaks than the 6 strand core.
Author: P-G. Voigt