1. Types of wire, lay and preforming affect
wire rope performance and operation
The basic types of wire Stainless steel wire This is a
used in ropes special alloy containing approximately
Bright wire Most ropes are made 18% chromium and 8% nickel. It has
Preforming with uncoated (bright) wire that is high resistance to many corrosive
preshapes manufactured from high-carbon steel. conditions and is used extensively
strands before The chemistry of the steel used and the
the rope in yachting ropes and control cables.
is closed. practice employed in drawing the wire
are varied to supply the ultimate combi-
nation of tensile strength, fatigue Wire rope grades
resistance and wear The most common grade of rope today
resistance in the is called Extra Improved Plow Steel
finished rope. Grade (XIP®). For most ropes, this will
be the grade supplied. XIP ropes have
> Preforming helically
Galvanized wire This is often a 15% higher minimum breaking force
shapes the wires
used to improve corrosion resistance than most Improved Plow Steel Grade
and strands into
of wire ropes. We use the following two (IPS), the former standard strength.
the shape they
different procedures to manufacture
will assume in the
galvanized wire: Other grades of wire rope are
finished rope. It also available, including Extra
improves handling
Galvanized to finished size wire Extra Improved Plow Steel Grade
and resistance
is first drawn as a bright wire to a (XXIP ®). Many equipment designers
to kinking by
predetermined size that’s smaller than are specifying XXIP grade wire rope
conforming the
the required finished wire size. This for the operating ropes on modern
strands to the
wire is then run through the galvanizing higher-rated equipment. They’re
position they
line, and the resultant coating of zinc taking advantage of its higher minimum
take in the rope.
increases the wire diameter to the breaking force to help reduce total
finished size. Galvanized to finished system weight. New machines can be
> The superior
size wire has a strength 10% lower designed with higher ratings using
qualities of
than the same size and type of bright smaller diameter rope due to XXIP’s
preformed ropes
wire. Ropes made from this wire higher strength. Minimum breaking
result from wires
therefore have a minimum breaking force of XXIP grade wire rope is 10%
and strands being
force that’s 10% lower than the higher than XIP grade. Ropes are
“at rest” in the rope,
equivalent size and grade of bright rope. available in all three grades – Improved
which minimizes Plow Steel (IPS), Extra Improved Plow
internal stresses
Drawn galvanized wire is galvanized Steel (XIP) and Extra Extra Improved
within the rope.
before the final drawing to finish size. Plow Steel (XXIP).
Today, preforming
Since the galvanized coating also goes
is virtually standard
through the drawing process, it is much
in most standard
thinner than the coating on galvanized
ropes, but specialty
to finished size wire. Drawn galvanized
ropes may be
wires are equal in strength to the same
non-preformed.
size and type of bright wire and drawn
galvanized rope is equal in strength to
the same size and grade of bright rope.
6 Union A WireCo WorldGroup Brand

2. “Lay” has three meanings in rope design
> Right lay – Regular lay
> Left lay – Regular lay
> Right lay – Lang lay
> Left lay – Lang lay
T
he first two meanings of “lay” 3. The length along the rope that a
are descriptive of the wire and strand makes one complete spiral
strand positions in the rope. The around the rope core. This is a
third meaning is a length measurement measurement frequently used in
used in manufacturing and inspection. wire rope inspection. Standards and
regulations require removal when a
1. The direction strands lay in the rope – certain number of broken wires per
right or left. When you look down a rope lay are found.
rope, strands of a right lay rope go
away from you to the right. Left lay
is the opposite. (It doesn’t matter The lay of a rope affects its
which direction you look.) operational characteristics
Regular lay is more stable and more
2. The relationship between the
resistant to crushing than lang lay. While
direction strands lay in the rope and lang lay is more fatigue resistant and
the direction wires lay in the strands. abrasion resistant, use is normally limited
In appearance, wires in regular lay to single layer spooling and when the rope
appear to run straight down the and load are restrained from rotation.
length of the rope, and in lang lay,
they appear to angle across the rope.
In regular lay, wires are laid in the
strand opposite the direction the
strands lay in the rope. In lang lay,
the wires are laid the same direction
in the strand as the strands lay in
the rope.
Union A WireCo WorldGroup Brand 7