Page 343 - The Tribology Handbook

Wire rope lubrication c12

THE ADVANTAGES OF
LUBRICATION

Increased fatigue life
Correct lubricants will facilitate individual wire adjust-
ment to equalise stress distribution under bending con-
ditions. An improvement of up to 300% can be expected
from a correctly lubricated rope compared with a similar
unlubricated rope.

RANGE OF
EXPECTED Figure 12.3 Typical severe corrosion pitting as-
IMPROVEMENT sociated with 'wash off' of lubricant by mine water
P
c
Increased abrasion resistance

"
PETROLATUM SOFT SEMI- HARD
TYPES BITUMINOUS BITUMINOUS
TYPES TYPES
TYPE OF LUBRICANT

Figure 12.1 Percentage increases in fatigue life of
lubricated rope over unlubricated rope Figure 12.4 Typical abrasion condition which can be
limited by the correct service dressing

LU B R lCATl0 N D U RING
MANUFACTURE

The Main Core Fibre cores should be given a suitable
dressing during their manufacture. This is more effective
than subsequent immersion of the completed core in heated
Increased corrosion resistance grease.
Independent wire rope cores are lubricated in a similar
way to the strands.
The Strands The helical form taken by the individual
wires results in a series of spiral tubes in the finished strand.
These tubes must be filled with lubricant if the product is
to resist corrosive attack. The lubricant is always applied
at the spinning point during the stranding operation.
The Rope A number of strands, from three to fifty, will
form the final rope construction, again resulting in voids
which must be filled with lubricant. The lubricant may be
applied during manufacture at the point where the strands
are closed to form the rope, or subsequently by immersion
through a bath if a heavy surface thickness is required.
Dependent on the application the rope will perform, the
lubricant chosen for the stranding and closing process
will be either a petrolatum or bituminous based compound.
For certain applications the manufacturer may use special
techniques for applying the lubricant.
Figure 12.2 Typical effect of severe internal corro- Irrespective of the lubrication camed out during rope
sion. Moisture has caused the breakdown of the fibre manufacture, increased rope performance is closely asso-
core and then attacked the wires at the atrandcore ciated with adequate and correct lubrication of the ropr
interface in service.

(32.1