What is the difference between WSC and IWRC?

Wire Rope’s 3 Basic Components

While few in number, these vary in both complexity and configuration so as to produce ropes for specific purposes or characteristics. The three basic components of a standard wire rope design are: 1) wires that form the strand, 2) multi-wire strands laid helically around a core, and 3) the core (Fig. 1).

Wire, for rope, is made in several materials and types; these include steel, iron, stainless steel, monel, and bronze. By far, the most widely used material is high-carbon steel. This is available in a variety of grades each of which has properties related to the basic curve for steel rope wire. Wire rope manufacturers select the wire type that is most appropriate for requirements of the finished product.

Grades of wire rope are referred to as traction steel (TS), mild plow steel (MPS), plow steel (PS), improved plow steel (IPS), extra improved plow steel (EIPS), and extra extra improved plow steel (EEIPS). (These steel grade names originated at the earliest stages of wire rope development and have been retained as references to the strength of a particular size and grade of rope.) The plow steel strength curve forms the basis for calculating the strength of all steel rope wires; the tensile strength (psi) of any steel wire grade is not constant, it varies with the diameter and is highest in the smallest wires.

The most common finish for steel wire is “bright” or uncoated. Steel wires may also be galvanized, i.e. zinc coated. “Drawn galvanized” wire has the same strength as bright wire, but wire “galvanized at finished size” is usually 10% lower in strength. In certain applications, “tinned” wire is used, but it should be noted that tin provides no sacrificial, i.e. cathodic, protection for the steel as does zinc. For other applications, different coatings are available.

“Iron” type wire is actually drawn from low-carbon steel and has a fairly limited use except in older elevator installations. When, however, iron is used for other than elevator applications, it is most often galvanized.

Stainless steel ropes, listed in order of frequency of use, are made of AISI types 302/304, 316, and 305. Contrary to general belief, hard-drawn stainless Type 302/304 is magnetic. Type 316 is less magnetic, and Type 305 has a permeability low enough to qualify as non-magnetic.

Monel metal wire is usually Type 400 and conforms to Federal Specification QQ-N-281.
Bronze wire is usually Type A Phosphor Bronze although other bronzes are specified at times.
Strands are made up of two or more wires, laid in any one of many specific geometric arrangements, or in a combination of steel wires with some other materials such as natural or synthetic fibers. It is conceivable that a strand can be made up of any number of wires, or that a rope can have any number of strands. The following section, IDENTIFICATION and CONSTRUCTION, provides a complete description of wire rope constructions.

The core is the foundations of a wire rope; it is made of materials that will provide proper support for the strands under normal bending and loading conditions. Core materials include fibers (hard vegetable or synthetic) or steel. A steel core consists either of a strand or an independent wire rope. The three most commonly used core designations are: fiber core (FC), independent wire rope core (IWRC), and wire strand core (WSC) (Fig. 2). Catalog descriptions of the various available ropes always include these abbreviations to identify the core type.

To summarize: a wire rope consists, in most cases, of three components: wires, strands, and a core (Fig. 1). To these may be added what can be considered a fourth component: the wire rope’s lubricant – a factor vital to the satisfactory performance of most operating ropes.

Construction of wire rope

The design of a rope is determined by
* STRAND CONSTRUCTION
The number and arrangement of wires in each strand
* ROPE CONSTRUCTION
The number and arrangement of strands in each rope
* THE CORE
A wire rope is much more than a collection of wires, even the finest quality of wires has a centre core, it may consist of Fiber, standed Wire, Synthetic material or a complete "Independent" Wire Rope within a wire rope.
The strand centre is a wire or fiber above which the covering wires are laid.
This centre wire is know as the king wire.
The rope is a number of strands laid helically around the core.
The most common construction consists of 6 stands laid around a fiber core or Independent Wire rope Gore as FMC or IWRC/WSC.

Wire Rope Lay
Right Lay : Clockwise
Left Lay : Counter-clockwise
Regular Lay : Wires in strands are laid in the opposite direction of the strands and are parallel to the rope axis. Ropes with regular lay are easy to handle and have greater resistance to crushing than those with lang lay.
Lang lay : Wires are laid in the same direction as the strands of the rope, and in an angle to the rope axis. Longer lengths of the individual wires are exposed, creating greater resistance to wear and improved flexibility. Lang Lay ropes should only be used where both rope ends are "fixed" and therefore, not be used with a swivel type terminal

How to Handle Steel Wire Rope
Winding Method of Drum or Winch

How to Measure Rope Size
The number and size of wires in a strand, and the number of strands in a rope vary according to the work the rope has to do. Strength, flexibility, abrasion resistance and other characteristic dictate the rope you ultimately select. The equipment has also to be considered when using ropes, the type and size of drum and pulley, the load and the speed at which the rope will work, is sometimes thought that a rope with the highest breaking strength is the best of the job. This is not always the case. For example a rope made from 180 kgf/mm2 wire with its superior ductility and flexibility may out-perform a rope of say 200 kgf/mm2 in the same construction with reduced ductility due to its higher tensile.
PS = Plow Steel,
IPS = Improved Plow Steel
EIPS = Extra Improved Plow Steel
Grade = = Indian Standard Grade (kg/mm2)
IWRC/WSC = Independent Wire Pope Core / Steel Core.

Rope Recommendations:
All Ropes are right-hand, regular lay (ordinary lay) (unless otherwise stated)
Uses:
For Drilling, Shipping Marine, Logging, Aircraft, Lifting Slings, Fishing, Excavating, Mining, Aerial Tramways, Ropeways and Suspension Structures.
Flexibility and Durability:
When compared with the ropes of same diameter, the ropes having more wires is more flexible than that having fewer wires, but reduces it's durability.
Can be Approved:
Indian Standard Institute, Indian Register of Shipping, American Petroleum Institute, Lloyd's Register of Shipping, American Bureau of Shipping, Det Norske Veritas, Bureau Veritas of Shipping, however all our supplies will a company with Test Certificate of Manufacturers and Dock Workers (Safety, Health & Welfare) Regulations 1990.

Cores for wire ropes
* Steel IWRC (Independent Wire Rope Core) The main core is an independent wire rope, normally having the construction 7x7 WSC (Wire Strand Core) The main core is an independent wire strand, normally having the same construction as the outer strands of the rope.
* Fiber Fiber cores are stranded and comprise either: Natural fibers such as sisal, hemp, jute, and cotton.
Synthetic fibers such as polyamide, polyetheylene, and polypropylene. Asbestos fibers (heat resistant)

Preformed ropes
In the preforming process the wires and strands are given their final helical pitch before being laid up into rope. Ropes made in this way show no tendency to untwist when cut.

Lubrication
Lubrication reduces internal friction of the wires and strands and protects against corrosion. Grease is applied to all rapes supplied. If special lubricants are required this must be specifically stated at time of ordering.

Diameter of wire ropes
The diameter of a wire rope is the diameter of the circle which incloses all of the wires.
When measuring wire rope it is important to take greatest distance of the outer limits of the 'Crowns' of two opposite strands. A measurement across the valleys will result in incorrect lower readings.

Useful chart for wire rope selection