The low temperature aging phenomena of Ultra High Tensile, (1960 grade ropes and above, UHT) mine winding ropes, whilst in storage. Practical cases studies from the South African mining industry.
Aging is a phenomenon that occurs naturally in steel. The simplest form of explanation is that it involves the movement of the small carbon atoms within the lattice of larger iron atoms, so that they collect at sites called dislocations. The net result in steel wire ropes of high carbon content is to cause brittleness and the rate at which this happens is dependent on storage temperature, tensile and time, (the three “T’s”). The manufacturer must produce wire that is minimally susceptible to aging, which was the case for this study, and this paper highlights the need for rope users to keep very high strength ropes with tensiles of 1960 grade ropes and above, as cool as possible during storage. This paper seeks to inform the mining industry by offering three actual South African Mine examples to conclusively prove that Low Temperature Aging will cause rope discard before installation if the ropes are not stored correctly.
Author(s): R. Wilson