Wire Rope - PDF

MYSTERIES OF WIRE ROPE 1. Basic components of wire rope 2. Strand patterns 3. Basic core types 4. Finish of wire ropes 5. Grades of wire ropes 6. Classification of wire rope 7. Basic Lay types of wire rope 8.Other types of wire ropes (including Rotation resistant a/o non- rotating type) 9. End te...

MYSTERIES OF WIRE ROPE 1. Basic components of wire rope 2. Strand patterns 3. Basic core types 4. Finish of wire ropes 5. Grades of wire ropes 6. Classification of wire rope 7. Basic Lay types of wire rope 8.Other types of wire ropes (including Rotation resistant a/o non- rotating type) 9. End terminations of wire rope 10. Lubrication of wire rope 11. Diameter of wire rope & Meausuring 12. Wire rope clips & correct rigging 13. Wire rope socks 14. Thimble 15. Certificate of wire ropes 16. How to order wire ropes on ARKAS FLEET as per SMS 17. Approval & Manufacturer marking of the wire rope 18. How to be checked when received 19. How to protect the spare wire ropes 20. ARKAS SMS regarding wire ropes 21. Wire rope renewal criteria 22. Guidelines for wire rope inspection Basic Components of wire rope Strand Patterns The number of layers of wires, the number of wires per layer, and the size of the wires per layer all affect the strand pattern type. Wire rope can be constructed using one of the following patterns, or can be constructed using two or more of the patterns below. Single Layer – The most common example is a 7 wire strand with a single-wire center and six wires of the same diameter around it. Filler Wire – Two layers of uniform-size wire around a center with the inner layer having half the number of wires as the outer layer. Small filler wires, equal to the number in the inner layer, are laid in valleys of the inner wire. Seale – Two layers of wires around a center with the same number of wires in each layer. All wires in each layer are the same diameter. The large outer wires rest in the valleys between the smaller inner wires. Warrington – Two layers of wires around a center with one diameter of wire in the inner layer, and two diameters of wire alternating large and small in the outer later. The larger outer-layer wires rest in the valleys, and the smaller ones on the crowns of the inner layer. Combination – A combination strand is constructed using any combination of two or more of the patterns listed above. Preformed or Non-Preformed - On a preformed wire rope, the strands and wires are formed during the manufacturing process to the helical shape that they will take in a finished wire rope. Preformed rope can be advantageous in certain applications where it needs to spool more uniformly on a drum, needs greater flexibility, or requires more fatigue-resistance when bending. Basic Core types of wire rope Core types of steel wire ropes; a) FC b) WSC c) IWRC The three basic wire rope cores. The core is the foundation of a wire rope. If the core cannot support the compressive load imposed, the rope will lose its clearance between strands and its service life will be shortened. Steel cores (WSC or IWRC) should be used when there is any evidence that a fiber core will not provide adequate support. Also, if the temperature of the environment may be expected to exceed 180º (82ºC) steel cores must be used. 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. Finish of Wire ropes 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. Grade of Wire Ropes The strength of wire rope is broken down into different grades, including: Improved Plow Steel (IPS) Extra Improved Plow Steel (EIPS) is 15% stronger than IPS Extra Extra Improved Plow Steel (EEIPS) is 10% stronger than EIPS The plow steel strength curve forms the basis for calculating the strength of most steel rope wires. The classifications of Wire Rope It provides the total number of strands, as well as a nominal or exact number of wires in each strand. These are general classifications and may or may not reflect the actual construction of the strands. However, all wire ropes of the same size and wire grade in each classification will have the SAME strength and weight ratings and usually the same pricing. A wire rope's classification includes two numbers (such as 6 x 19). The first number (6, in this example) represents the exact number of strands in the rope. The second number represents the number of wires in each strand, but this number identifies a class, or range and may not be an exact number of wires. The table below shows some of the most common wire rope configurations arranged in specific classifications. Classification Outer Strands Wires / Strand 6 x7 6 3–14 6 x 19 6 15–26 6 x 36 6 27–49 6 x 61 6 50–74 6 x 91 6 75–109 7 x 19 7 15–26 7 x 36 7 27–49 8x7 8 3–14 8 x 19 8 15–26 8 x 36 8 27–49 8 x 61 8 50–74 Basic lay types of wire rope Typical wire rope lays: a) right regular lay, b) left regular lay, c) right lang lay, d) left lang lay, e) right alternate lay. Wire rope identification is not only done by its component parts, but also by its construction, i.e., by the way the wires have been laid to form strands, and by the way the strands have been laid around the core. Direction and type of lay refer to the way the wires are laid to form a strand (either right or left) and how the strands are laid around the core (regular lay, lang lay, or alternate lay). Regular Lay – The wires line up with the axis of the rope. The direction of the wire lay in the strand is opposite to the direction of the strand lay. Regular lay ropes are more resistant to crushing forces, are more naturally rotation-resistant, and also spool better in a drum than lang lay ropes. Lang Lay – The wires form an angle with the axis of the rope. The wire lay and strand lay around the core in the same direction. Lang Lay ropes have a greater fatigue-resistance and are more resistant to abrasion. Alternate Lay – The wire rope consists of alternating regular lay and lang lay strands—used mainly for special applications. EXAMPLE 1″ 6 x 25 FW EIP RRL IWRC This wire rope description would provide the user with the following information: Diameter = 1″ Number of Strands = 6 Number of Wires Per Strand = 25 Strand Pattern = Filler wire Grade = Extra Improved Plow Steel Direction and Lay = Right Regular Lay Core Type = Independent Wire Rope Core Other types of wire rope These are special constructions and designed for special lifting applications. Rotation Resistant Wire Rope Some types of wire rope, especially lang lay wire rope, are more susceptible to rotation when under load. Rotation resistant wire rope is designed to resist twisting, spinning, or rotating and can be used in a single line or multi-part system. Special care must be taken when handling, unreeling, and installing rotation resistant wire rope. Improper handling or spooling can introduce twist into the rope which can cause uncontrolled rotation. Compacted Strand Wire Rope Compacted strand wire rope is manufactured using strands that have been compacted, reducing the outer diameter of the entire strand, by means of passing through a die or rollers. This process occurs prior to closing of the rope. This process flattens the surface of the outer wires in the strand, but also increases the density of the strand. This results in a smoother outer surface and increases the strength compared to comparable round wire rope (comparing same diameter and classification), while also helping to extend the surface life due to increased wear resistance. Compacted / Swaged Wire Rope A swaged wire rope differs from a compacted strand wire rope, in that a swaged wire rope’s diameter is compacted, or reduced, by a rotary swager machine after the wire rope has been closed. A swaged wire rope can be manufactured using round or compacted strands. The advantages of a swaged wire rope are that they are more resistant to wear, have better crushing resistance, and high strength compared to a round strand wire rope of equal diameter and classification. However, a swaged wire rope may have less bending fatigue resistance. Plastic Coated Wire Rope A plastic coating can be applied to the exterior surface of a wire rope to provide protection against abrasion, wear, and other environmental factors that may cause corrosion. However, because you can’t see the individual strands and wires underneath the plastic coating, they can be difficult to inspect. Plastic Impregnated (PI) Wire Rope Plastic filled wire ropes are impregnated with a matrix of plastic where the internal spaces between the strands and wires are filled. Plastic filling helps to improve bending fatigue by reducing the wear internally and externally. Plastic filled wire ropes are used for demanding lifting applications. Plastic Coated or Plastic Filled IWRC Wire Rope This type of wire rope uses an Independent Wire End Terminations of wire rope The rope end must be fastened to the mechanism so that force and motion are transferred efficiently. End terminations thus become items of great importance for transferring these forces. Each basic type of termination has its own individual characteristic. Hence, one type will usually fit the needs of a given installation better than the others. It should be noted that not all end terminations will develop the full strength of the wire rope used. To lessen the possibility of error, the wire rope industry has determined terminal efficiencies for various types of end terminations. Holding power calculations can be made for the more popular end terminations based on efficiency factors in Table 5. End fittings or terminations are available in many designs, some of which were developed for particular applications. The six shown are among the most commonly used.based on efficiency factors in Table 5. Typical Wire Rope End Terminations Hand S!)ilced eye :O Swaged open socket Sl)licoo thimble I}:::,.'::s::s 0 Swaged dosed sock.et t l Swagec:1 th'earea