Plow Steel Wire Rope
Plow steel wire rope is unusually tough and strong.
This steel has a tensile strength of 220,000 to 240,000
psi. Plow steel wire rope is suitable for hauling, hoisting,
and logging.
Improved Plow Steel Wire Rope
Improved plow steel wire rope is one of the best
grades of rope available and is the most common rope
used in the NCF. This type of rope is stronger, tougher,
and more resistant to wear than either mild plow steel
or plow steel. Each square inch of improved plow steel
can stand a strain of 240,000 to 260,000 pounds. This
makes it especially useful for heavy-duty service, such
as on cranes with excavating and weight-handling
attachments.
LAYS OF WIRE ROPE
The term lay refers to the direction of the twist of
the wires in a strand and to the direction that the strands
are laid in the rope. In some instances, both the wires in
the strand and the strands in the rope are laid in the same
direction; and in other instances, the wires are laid in
one direction and the strands are laid in the opposite
direction, depending on the intended use of the rope.
Most manufacturers specify the types and lays of wire
rope to be used on their piece of equipment. Be sure and
consult the operators manual for proper application.
Five different lays of wire rope are shown in figure
13-4.
The five types of lays used in wire rope are as
follows:
. Right Regular Lay: In right regular lay rope, the
wires in the strands are laid to the left, while the strands
are laid to the right to form the wire rope.
. Left Regular Lay: In left regular lay rope, the
wires in the strands are laid to the right, while the strands
are laid to the left to form the wire rope. In this lay, each
step of fabrication is exactly opposite from the right
regular lay.
. Right Lang Lay: In right lang lay rope, the wires
in the strands and the strands in the rope are laid in the
same direction; in this instance, the lay is to the right.
. Left Lang Lay: In left lang lay rope, the wires in
the strands and the strands in the rope are also laid in the
same direction; in this instance, the lay is to the left
(rather than to the right as in the right lang lay).
Figure 13-4.Lays of wire rope.
. Reverse Lay: In reverse lay rope, the wires in
one strand are laid to the right, the wires in the nearby
strand are laid to the left, the wires in the next strand are
to the right, and so forth, with alternate directions from
one strand to the other. Then all strands are laid to the
right.
LAY LENGTH OF WIRE ROPE
The length of a rope lay is the distance measured
parallel to the center line of a wire rope in which a strand
makes one complete spiral or turn around the rope. The
length of a strand lay is the distance measured parallel
to the center line of the strand in which one wire makes
one complete spiral or turnaround the strand. Lay length
measurement is shown in figure 13-5.
Figure 13-5.Lay length of wire rope.
13-3
