COMPONENTS: Wire rope consists of three basic components.
1. Wires.
2. Strands, formed by wires, laid helically around a core.
3. Core, or center.
MATERIAL: Steel grades in wide use today are IPS (improved plow steel), EIPS (extra improved plow steel), EEIPS (extra extra improved steel). Types 302/304 and 316 are most common in stainless steel grades.
CORE: Its function is to provide proper support for the strands under normal conditions. Three types of core (or center) are commonly used.
1. Fiber Core (F.C.), usually polypropylene, sometimes hemp (H.C.) and sisal.
2. Independent Wire Rope Core (IWRC)
3. Wire Strand Core (WSC) IWRC and WSC are sometimes referred to as steel wire core or steel center.
CONSTRUCTION: Expressed in numbers of strands x number of wires. 6 x 25 indicates that the wire rope consists of 6 strands, which in turn have 25 individual wires. Constructions are grouped into classes:
STRAND PATTERNS: They refer to different types of arrangements of wire and their diameters within a strand.Common strand patterns are Filler Wire, Seale, Warrington and combinations thereof.
LAY: Indicates how the wires have been laid to form strands and how the strands have been laid around the core.A right regular lay rope (RRL; the most common) has its strands laid right on the rope - similar to threading a right-hand threaded bolt. Regular means that the direction of the wire lay in the strand is opposite to the direction of the strand lay in the rope.(The wires in regular lay rope appear to be in line with the axis of the rope).
CAUTION: Different lay wire rope should not be used combined into a single line. Rotation of the connection can cause low force break.
PERFORMING: A manufacturing process wherein the strands and their wires are permanently formed - during fabrication - to the helical shape that they will ultimately assume in the finished wire rope. Proper preforming prevents the strands and wires from unlaying during normal use. The vast majority of wire rope sold today is preformed.
FINISH: Wire rope is either manufactured as “bright” (or “black”) - meaning uncoated, or galvanized for better corrosion resistance. “Drawn Galvanized” wire has the same strength as bright wire, but wire, “galvanized at finished size” is usually 10% lower in strength. Plastic coated wire rope is also available, usually galvanized or stainless steel cable. The most common plastic coatings are vinyl or nylon in either clear or white, although other materials and colors are available. These coatings do not add strength to the wire rope itself.
LUBRICATION: During fabrication, wire ropes receive lubrication. The kind and amount depends on the rope’s size, type and use, if known. This in-process treatment will provide the finished wire rope with ample protection for a reasonable time if it is stored under proper conditions. But, when the wire rope is put into service, the initial lubrication will normally be less than needed for the full useful life of the wire rope. Because of this, periodic applications of a suitable wire rope lubricant are necessary.
ORDERING WIREROPE: Construction, lay core, finish and other factors mentioned above impart greatly differing characteristics to different wire ropes. They must be understood and considered when selecting wire rope. There is no perfect wire rope for all applications; usually some less desirable properties are traded off for other, more desirable ones. Refer to the Wire Rope Users Manual by the American Iron & Steel Institute for a better understanding of wire properties and consult professional help when in doubt.
Lacking a complete description of the wire rope desired, a supplier can make several assumptions:
1. If direction and type of lay are omitted from the rope description, it is assumed to be right regular lay (RRL).
2. If finish is omitted, this will be presumed to mean ungalvanized, “bright” finish.
3. If no mention is made with reference to preforming, preformed wire rope will be supplied.
4. If a supplier receives an order for 6 x 19 wire rope he may assume this to be a class reference and is, therefore, legally justified in furnishing any construction within this category.
1. Wires.
2. Strands, formed by wires, laid helically around a core.
3. Core, or center.
MATERIAL: Steel grades in wide use today are IPS (improved plow steel), EIPS (extra improved plow steel), EEIPS (extra extra improved steel). Types 302/304 and 316 are most common in stainless steel grades.
CORE: Its function is to provide proper support for the strands under normal conditions. Three types of core (or center) are commonly used.
1. Fiber Core (F.C.), usually polypropylene, sometimes hemp (H.C.) and sisal.
2. Independent Wire Rope Core (IWRC)
3. Wire Strand Core (WSC) IWRC and WSC are sometimes referred to as steel wire core or steel center.
CONSTRUCTION: Expressed in numbers of strands x number of wires. 6 x 25 indicates that the wire rope consists of 6 strands, which in turn have 25 individual wires. Constructions are grouped into classes:
| 6 x 7 Class: Containing 6 strands that are made up of 3 - 14 wires, or
which no more than 9 are outside wires. 6 x 19 Class: Containing 6 strands that are made up of 15 - 26 wires, of which no more than 12 are outside wires. 6 x 37 Class: Containing 6 strands that are made up of 27 - 49 wires, of which no more than 18 are outside wires. 8 x 19 Class: Containing 8 strands that are made up of 15 - 26 wires, of which no more than 12 are outside wires. 19 x 7 Class: Containing 19 strands, each of which is made up of 7 wires. 8 x 19 and 19 x 7 class wire ropes have rotation-resistant properties, excluding elevator ropes. The constructions listed above are just some of the more popular constructions. |
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| Other Common Constructions: | 7 x 7, 7 x 19: | Galvanized cable. Sometimes referred to as “aircraft cable” but not intended for aircraft use. |
| 1 x 7, 1 x 19: | Strand | |
| 7 x 7 x 7, x 7 x 19: | Cable Laid | |
| Many
others exist, some for highly specialized applications only. Note that any class denotes the nominal number of wires in each strand. The actual number of wires may be different. For example: 6 x 37 class wire most commonly may consist of 36 wires, or 31, or 41. |
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STRAND PATTERNS: They refer to different types of arrangements of wire and their diameters within a strand.Common strand patterns are Filler Wire, Seale, Warrington and combinations thereof.
LAY: Indicates how the wires have been laid to form strands and how the strands have been laid around the core.A right regular lay rope (RRL; the most common) has its strands laid right on the rope - similar to threading a right-hand threaded bolt. Regular means that the direction of the wire lay in the strand is opposite to the direction of the strand lay in the rope.(The wires in regular lay rope appear to be in line with the axis of the rope).
CAUTION: Different lay wire rope should not be used combined into a single line. Rotation of the connection can cause low force break.
PERFORMING: A manufacturing process wherein the strands and their wires are permanently formed - during fabrication - to the helical shape that they will ultimately assume in the finished wire rope. Proper preforming prevents the strands and wires from unlaying during normal use. The vast majority of wire rope sold today is preformed.
FINISH: Wire rope is either manufactured as “bright” (or “black”) - meaning uncoated, or galvanized for better corrosion resistance. “Drawn Galvanized” wire has the same strength as bright wire, but wire, “galvanized at finished size” is usually 10% lower in strength. Plastic coated wire rope is also available, usually galvanized or stainless steel cable. The most common plastic coatings are vinyl or nylon in either clear or white, although other materials and colors are available. These coatings do not add strength to the wire rope itself.
LUBRICATION: During fabrication, wire ropes receive lubrication. The kind and amount depends on the rope’s size, type and use, if known. This in-process treatment will provide the finished wire rope with ample protection for a reasonable time if it is stored under proper conditions. But, when the wire rope is put into service, the initial lubrication will normally be less than needed for the full useful life of the wire rope. Because of this, periodic applications of a suitable wire rope lubricant are necessary.
ORDERING WIREROPE: Construction, lay core, finish and other factors mentioned above impart greatly differing characteristics to different wire ropes. They must be understood and considered when selecting wire rope. There is no perfect wire rope for all applications; usually some less desirable properties are traded off for other, more desirable ones. Refer to the Wire Rope Users Manual by the American Iron & Steel Institute for a better understanding of wire properties and consult professional help when in doubt.
Lacking a complete description of the wire rope desired, a supplier can make several assumptions:
1. If direction and type of lay are omitted from the rope description, it is assumed to be right regular lay (RRL).
2. If finish is omitted, this will be presumed to mean ungalvanized, “bright” finish.
3. If no mention is made with reference to preforming, preformed wire rope will be supplied.
4. If a supplier receives an order for 6 x 19 wire rope he may assume this to be a class reference and is, therefore, legally justified in furnishing any construction within this category.
