Microstructural manifestations of fractured Z-profile steel wires on the outer layer of a failed locked coil wire rope
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Locked coil wire ropes, by virtue of their unique design and construction, have specialized applications in aerial ropeways, mine hoist installations, suspension bridge cables, and so forth. In such specialty ropes, the outer layer is constructed of Z-profile wires that provide not only effective interlocking but also a continuous working surface for withstanding in-service wear. The compact construction and fill-factor of locked coil wire ropes make them relatively impervious to the ingress of moisture and render them less vulnerable to corrosion. However, such ropes are comparatively more rigid than conventional wire ropes with fiber cores and therefore are more susceptible to the adverse effects of bending stresses. The reasons for premature in-service wire rope failures are rather complex but frequently may be attributed to inappropriate wire quality and/or abusive operating environment. In either case, a systematic investigation to diagnose precisely the genesis of failure is desirable.
This article provides a microstructural insight into the causes of wire breakages on the outer layer of a 40 mm diameter locked coil wire rope during service. The study reveals that the breakages of Z-profile wires on the outer rope layer were abrasion induced and accentuated by arrays of fine transverse cracks that developed on a surface martensite layer.
Keywordslocked coil wire rope surface martensite wire breakage Z-profile wire
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- 1.T. Gladman: “Medium/High Carbon Steels for Rails, Rods, Bars and Forgings,”Materials Science and Technology: A Comprehensive Treatment, vol. 7, F.B. Pickering, ed., VCH Publishers Inc., 1991, pp. 420–21.Google Scholar
- 2.G.A. Sharp: “Steel Wire for Ropes,”Steel Wire Handbook, vol. 3, A.B. Dove, ed., The Wire Association Inc., Branford, CT, 1972, pp. 77–94.Google Scholar
- 3.F.R. Hutchings and P.M. Unterweiser:Failure Analysis—The British Engine Technical Reports, American Society for Metals, 1981, pp. 359–60.Google Scholar
- 4.“Wear Resistance of Steels,”ASM Specialty Handbook: Carbon and Alloy Steels, J.R. Davis, ed., ASM International, 1996, p. 170.Google Scholar
- 5.F.L. Jamieson: “Failures of Lifting Equipment,”Failure Analysis and Prevention, vol. 11,ASM Handbook, 9th ed., K. Mills, J.R. Davis, J.D. Destefani, D.A. Dietrich, G.M. Crankovic, and H.J. Frissell, ed., ASM International, 1986, pp. 514–21.Google Scholar