to Wire Rope
• Criteria for Selecting Wire-Rope
• Care and Use of Wire Rope
• Wire Rope Specifications
Wire rope is a machine with dozens–even
hundreds– of individual wires which are formed and fabricated
to move or operate at close tolerances to one another. When a wire
rope bends, each of its many wires slides and adjusts to accommodate
the differences in length between the inside and outside of the bend.
The sharper the bend, the greater the movement.
Every wire has three basic components: the wires, strands and core.
The core may be either fiber (FC) such as sisal, manila or jute, or
an Independent Wire Rope Core (IWRC), which is actually a smaller
wire rope within the strands of the outer wire rope.
The wires are predominantly constructed from high-carbon steel, but
may also be formed from various metals such as iron, stainless steel,
monel or bronze. Carbon steel wire rope is manufactured in various
grades, including Improved Plow Steel (IPS), Extra Improved Plow Steel
(EIPS) and Extra Extra Improved Plow Steel (EEIPS), which designate
the nominal strength of the wire rope. EIPS is the most commonly used
and manufactured grade today.
Wire rope generally comes with a "bright" or uncoated finish
but several other options are available. A galvanized, zinc coating,
a tin coating or a synthetic coating such as vinyl or nylon may also
be applied to the rope's surface. Ropes with plastic coatings and
plastic-filled interiors are also obtainable. It should be understood
that these coatings can affect the characteristics and breaking strength
of the wire rope.
Wire ropes are identified by classifications based upon the number
of strands and nominal number of wires in each strand. A 6 x 19 classification
for example, includes six strands with each strand consisting of 15-26
individual wires. The six strands of a 6 x 37 class wire rope are
constructed of 27-49 individual wires. Other popular classifications
include 19 x 7, 7 x 19 and 8 x 19.