Rouge (or red rouge) is a fine, red iron oxide which forms on the rope, giving it
a “rusty” appearance and suggesting that advanced deterioration is taking place.
Rouging is caused by fretting, a special type of abrasion which occurs when two
solid surfaces bear against one another, while under a heavy load and subjected
to small amplitude vibrations. The small amplitude vibrations are due to load
vibrations which occur during loading and unloading, and starting and stopping
of the elevator. The pressures from the heavy load and vibrations work out any
lubrication that may have been present, and result in very small metal particles
that have become abraded or torn out of the metal surface. These particles spontaneously
oxidize in the air to form the red ferric oxide dust that is characteristic of rouging.
Rouge is different from what we commonly refer to as rust. Rust forms when
moisture is introduced to a metal surface. When combined with this moisture, the
metal surface, itself, rusts. Rouge does not indicate that a wire rope is beginning
to rust. Rouging, instead, means that abrasion is occurring between the wire
rope components and that only the small metal particles, now separate from the
wire rope, are rusting. In elevator rope, rouging begins with a lack of core support.
This is usually due to a lack of proper field lubrication. The fiber core dries up.