01 - WIRE ROPE & STRAND
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Characteristics of Lay
RIGHT HAND ORDINARY LAY
RIGHT HAND LANG’S LAY
LEFT HAND LANG’S LAY
LEFT HAND ORDINARY LAY
ONE ROPE LAY
The direction of rope Lay does not affect the breaking force of
a rope. However, the combination of strand lay and rope lay will
greatly affect the rope characteristics and this factor must be
taken into consideration when choosing a rope. Although the lay
length can slightly affect rope behaviour the dominant aspect
that influences performance is the direction of lay and whether
it is Lang’s Lay or Ordinary Lay. For example, the importance
of rope lay is evident in a four-part high lift grab where rotation
of the grab is prevented by the use of alternate right-hand and
When a rope is operated over a drum or sheave, the strands
and wires move relative to one another. To reduce the resultant
friction within the rope as well as the friction between the rope
and drum or sheave, ropes are lubricated in manufacture.
In addition this lubrication also retards corrosion and inhibits
possible rotting of the fibre core. In special applications a
combination of lubricants may be required for example, the
core and inner wires of the strands may be heavily lubricated
while the lighter lubrication may be applied to outer wires and
Wire rope cores are normally heavily lubricated irrespective
of the outer strand lubrication. Regular lubrication is more
beneficial than applying large amounts infrequently.
All ropes are produced to comply with the requirements of the
Australian Standards. These specifications require wire to be
produced to AS1394. All ropes comply to AS3569 Steel Wire
The company’s testing facilities are constantly engaged on
the testing of both works production and samples received for
For investigation and customer service purposes, a non-
destructive testing unit, operated by Bullivants trained staff is
available. Enquiries concerning use of this equipment or advice
on non-destructive testing please contact your local Bullivants
branch. A full report of all site examination is issued.
Steel Quality - Tensile Strength
Production methods, equipment and quality control in
steelmaking and wire drawing ensure that wire rope conforms
to Australian and International Standards.
Wire ropes are usually supplied in the following tensile
Minimum Tensile Abbreviated
NOTE: G1770 (Galvanised 1770 Mpa) is the preferred grade
for galvanised ropes other than standard multiple operation
ropes of 6 x 7, 6 x 19, 6 x 24 and 6 x 36 Construction.
However, other special tensile ranges can be supplied in
both galvanised and black as follows: 1220 MPa, 1420 MPa,
1970 MPa, 2070 MPa and 2250 MPa.
With the increasing use of heavy-duty and more compact
equipment (e.g. power winches on mobile cranes and mine
winding) there is a gradual upward trend in the required rope
wire tensile range. However, as factors other than strength
influence the life of wire rope, the specification application must
be kept in mind when the tensile strength of the wire is selected.
Care and Maintenance
A wire rope may be looked upon as a machine composed of
a large number of moving parts. As such it should be broken
in as soon as it is installed, by loading it very lightly for a few
cycles and then gradually stepping up the load, to enable both
wires and strands to ‘bed down’ into the working positions,
with the load distributed as uniformly as possible.
The use of ‘spinners’ or swivels should be avoided whenever
possible. All ropes should be reeled onto winch drums as tightly
and uniformly as possible during the initial installation.
Lubrication impregnated into the rope during manufacture is not
sufficient to last the life of the rope. Additional lubrication should
be done during the service.
The frequency of lubrication in the field is determined by the
operating conditions of the rope e.g., high-speed heavy duty
operation calls for more frequent lubrication, as do wet and/or
For general purpose applications medium viscosity black oil is
considered suitable. For corrosive conditions a high penetrating,
water repellent rush-inhibiting oil should be used.
Wire rope is tough and durable, but nonetheless expendable
and eventually reaches the end of its safe service life.
Rope deterioration becomes noticeable through the
presence of broken wires, surface wear, corrosion, wire or
strand distortion due to mechanical abuse, or drastic reduction
in diameter and lengthening of the lay. Also deterioration can be
detected by the use of non-destructive testing techniques. Wire
ropes should periodically be inspected for signs of deterioration.
Wire Rope Terms
Minimum Breaking Force (MBF)
MBF is the minimum load or force, guaranteed by the
manufacturer after which the rope will break. It is based on the
use of wires of nominal size and the minimum tensile strength.
This is the figure which should be used for design of rope
The measurement across the centre line of the circle
circumscribing the outer wires of a strand or the outer
strands of a rope.
Term applied to the required ratios of rope breaking force to
total rope force due to load. Normally set by Statutory bodies,
e.g. Mines Departments, Navigation Departments, Lifts and