Wire Rope Glossary

Glossary of Wire Related Terminology

Annealing – This means putting a material in its soft condition. Annealing is different for each of the three metallurgical structures.

Cast – The diameter that a single ring of wire will take when placed on a horizontal surface.

Catch Weight Coils – This is normally how wire is ordered. These are random weight coils as taken off the drawing machines. Normally, the weight variance is ± 25 lbs.

Ductility – The amount of plastic deformation a material will endure prior to fracture. Usually reported as elongation or reduction of area.

Elongation – The percent of length the wire will stretch prior to breaking in tension. Usually determined using a 2″, 6″ or 10″ length. % Elongation = 100 X (Final Length / Original Length Original Area)

Hardness – A measure of a material’s resistance to indentation. For wire, normally the Rockwell Test or one of the superficial hardness tests are used.

Metallurgical Structures – Stainless steels are classified into 3 major groups depending on the internal arrangement of atoms – austentic, ferritic, and martensitic.

  • Austenitic stainless steels have a face centered cubic (FCC) structure. These alloys are the chromium-nickel stainless steels known as the 300 series (302, 304, etc.). They are hardenable only by cold working and have excellent corrosion resistance especially to stress corrosion cracking.
  • Ferritic stainless steels have a body centered cubic (BCC) structure. These alloys are the chromium stainless steels containing low carbon levels. They are hardenable primarily by cold working, although some will harden slightly by heat treating. Ferritic stainless steels work harden much slower than austenitic stainless steels.
  • Martensitic stainless steels have a body centered tetragonal (BCT) structure. These alloys are chromium stainless steels with medium to high carbon levels. They work harden slowly in the annealed (soft) condition but can be heat-treated to very high tensile strengths.

Reduction of Area – The percent of cross-sectional area the wire will “Neck Down” prior to break in tension. % R.A. = 100 X (Original Area – Area After Fracture / Original Area)

Peak – The vertical distance between the opposite ends of a single ring of wire when placed on a horizontal surface. Sometimes determined when the ring is held vertically.

SAFE WORKING LOAD – Briefly defined, the “safe working load” (SWL) of a line is the load that can be applied without causing any kind of damage to the line. Note that the safe working load is considerably less than the breaking strength. A wide margin of difference between breaking strength and safe working load is necessary to allow for such factors as additional strain imposed on the line by jerky movements in hoisting or bending over sheaves in a pulley block.

SAFETY FACTOR – Safety factor of a line is the ratio between the breaking strength and the safe working load. Usually, a safety factor of 4 is acceptable, but this is not always the case. In other words, the safety factor will vary, depending on such things as the condition of the line and circumstances under which it is to be used. While the safety factor should NEVER be less than 3, it often should be well above 4 (possibly as high as 8 or 10). For best, average, or unfavorable conditions, the safety factor indicated below may often be suitable. Stress relieving – Reducing residual stresses put into the wire during cold working by heating to a temperature range of 400 degrees F – l000 degrees F.

Ultimate Tensile Strength (UTS) – The stress (breaking load = cross-sectional area) at which the wire will break. Sometimes referred to as the breaking strength.

Yield Strength (YS) – The stress (load/area) at which the wire changes from elastic to plastic in behavior, i.e. takes a permanent set.

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