Product: Winches &
High Capacity Hoists
Models: All
Subject : Wire Rope Chart
By: Steve Kaukl, Product & Technical
Sales Specialist
No. UL-020
Date: 4/20/00
The following wire rope
chart is provided for your reference. It is based on
a 6 x 19 and 6 x 37
Class, Independent Wire Rope Core (IWRC), Extra Improved
Plow Steel (EIPS) wire rope. Along with the basic information
we have included columns showing the wire ropes working
capacity at both a 5:1 and a 3.5:1 design factor. Ingersoll-Rand
follows ANSI/ASME* in recommending that you use a:
- 3.5:1 design factor for wire ropes used
in most winching applications (e.g. pulling/hauling and
anchor handling).
- 5:1 design factor for wire ropes used
for lifting and lowering applications.
The 6 x 19 and 6 x 37 class wire ropes cover
a wide variety of winching and lifting applications. The
basic differences are shown below.
What makes them different:
- The 6 x 19 Class uses fewer wires (15-26)
of a larger diameter, to provide a greater degree of abrasion
resistance. This is useful in applications such as excavating,
logging, and mining where the rope is constantly being
pulled over the ground or rough, uneven surfaces.
- The 6 x 37 Class uses more wires (24-49)
of a smaller diameter for increased flexibility and fatigue
resistance. This enables the wire rope to better endure
the excessive bending it encounters in applications where
small diameter drums and directional sheaves (with poor
D/d ratios) are found.
Since we mentioned D/d ratios . . . What
is a D/d ratio and how does it affect the size of the wire
rope I put on a given drum?
The relationship between the wire rope diameter
as it is bent around the Drum
diameter is expressed as a Dd ratio/ The smaller the ratio, the shaper
the bend a wire rope must make as it spools around a drum.
Imagine how a garden hose (fig. 1.) (d) would bend and kink if you
tried to wrap it around the small diameter of a pencil (D ).
Why is the D/d ratio so important?
Using a smaller than recommended D/d ratio
aggravates this bending motion thereby causing fatigue,
irregular wear and accelerated deterioration (fig. 2). This
increased wear usually results in more frequent inspections
and costly wire rope replacement in order to avoid unexpected
failures. For this reason Ingersoll-Rand and most wire rope
manufacturers conform to *ANSI/ASME which recommends a minimum
of 15:1 (D/d) ratio for pulling/hauling applications and
a minimum of 18:1 (D/d) ratio for lifting and lowering applications.
A tightly spiraled pig tailed rope; this
condition is a result of the rope being pulled around an
object that has a small diameter.
Drum crushing and spiraling in a winch line.
This is caused by the small drums, high loads, and multiple
layer winding conditions frequently found on winches.
How do you calculate the D/d ratio?
Add the diameter of the drum barrel to the
diameter of the wire rope you want to use. Divide by the
diameter of the wire rope.
Example: when using 1/2" wire rope on
a 10.75" drum barrel.
10.75" + .5" = 11.25"
11.25 divided by .5 = 22.5:1 D/d ratio
This meets the *ANSI/ASME recommendation
of 15:1 for pulling and the 18:1 for lifting applications.
Wire Rope Chart (Wire
rope, bright, IWRC, 6 x 37, or 6 x 19, EIPS)
|
Wire Rope Size
|
Nominal
Strength |
Weight
|
Recommended
Safe Working Load At |
| US
Tons |
Metric
Tons |
Lbs.
Per Foot |
Kg.
Per meter |
5:1
design factor (lbs.) |
5:1
design factor (kg.) |
3.5:1
design factor (lbs.) |
3.5:1
design factor (kg) |
| 1/4 |
3.4 |
3.1 |
.12 |
.17 |
1360 |
618 |
1943 |
883 |
| 5/16 |
5.27 |
4.8 |
.18 |
.27 |
2108 |
958 |
3011 |
1369 |
| 3/8 |
7.55 |
6.9 |
.26 |
.39 |
3020 |
1373 |
4314 |
1961 |
| 7/16 |
10.2 |
9.3 |
.35 |
.52 |
4080 |
1855 |
5829 |
2649 |
| 1/2 |
13.3 |
12.1 |
.46 |
.68 |
5320 |
2418 |
7600 |
3455 |
| 5/8 |
20.6 |
18.7 |
.72 |
1.07 |
8240 |
3745 |
11771 |
5351 |
| 3/4 |
29.4 |
26.7 |
1.04 |
1.55 |
11760 |
5345 |
16800 |
7636 |
| 7/8 |
39.8 |
36.2 |
1.42 |
2.11 |
15920 |
7236 |
22743 |
10338 |
| 1 |
51.7 |
47.0 |
1.85 |
2.75 |
20680 |
9400 |
29543 |
13429 |
| 1-1/8 |
65 |
59.1 |
2.34 |
3.48 |
26000 |
11818 |
37143 |
16883 |
| 1-1/4 |
79.9 |
72.6 |
2.89 |
4.30 |
31960 |
14527 |
45657 |
20753 |
| 1-3/8 |
96 |
87.3 |
3.50 |
5.21 |
38400 |
17455 |
54857 |
24935 |
*American National Standards Institute/The American Society
of Mechanical Engineers
