PREFORMING: A manufacturing process wherein the strands and their wires are permanently formed, during fabrication, the helical shape that they will ultimately assume in the finished wire rope. Proper preforming prevents the strand and wire from unlaying during normal use. The vast majority of wire ripe sold today is preformed.
FINISH: Wire rope is either sold 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 coverings are vinyl or nylon in either clear or white, although other materials and colors are available. These coating 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 a 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 WIRE ROPE: 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 one. Refer to the Wire Rope Users Manual by the Wire Rope Technical Board for a better understanding of wire rope properties and consult professional help when in doubt.
Lacking a complete description of the wire rope desired, a supplier can make several assumptions:
- If direction and type of lay are omitted from the rope description, it is assumed to be right regular lay (RRL).
- If finish is omitted, this will be presumed to mean ungalvanized, “bright” finish.
- If no mention is made with reference to preforming, preformed wire rope will be supplied.
- 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 identified in furnishing any construction within this category.