Sling Types - Wire Rope, Chain & Synthetic Materials
Characteristics, inspection criteria, and limitations of wire rope, alloy chain, and synthetic web/round slings.
- Describe wire rope sling construction, inspection criteria, and proper storage
- Identify alloy chain sling grades, temperature limits, and inspection criteria
- Explain synthetic web and round sling limitations including UV and chemical vulnerabilities
- Define proof testing requirements and tag/removal standards for all sling types
Lesson 1
Wire Rope Slings - Construction, Inspection & Storage
Wire Rope Construction
Wire rope slings are the most common sling type in heavy rigging. They are constructed from individual wires twisted into strands, which are then laid around a core. Common constructions include 6x19 and 6x37 (strands x wires per strand).
End Fittings
Wire rope slings terminate with fittings that form the eye or connection point:
- Mechanical splice (Flemish eye) - most common, maintains high efficiency
- Swaged fittings - compressed metal sleeves
- Poured sockets - zinc or resin filled, highest strength
- Wire rope clips - for field-made connections (not for slings in many jurisdictions)
Inspection and Removal Criteria
Wire rope slings must be removed from service when:
- 6 broken wires randomly distributed in one rope lay
- 3 broken wires in one strand in one rope lay
- Kinking, crushing, or birdcaging
- Evidence of heat damage (discoloration, loss of internal lubricant)
- End fitting damage - cracks, deformation, excessive wear
- Corrosion that pits the wire surfaces
- Reduction in diameter from the original measurement
Broken Wire Limits
Remember: 6 broken wires randomly in one lay or 3 broken wires in one strand in one lay per ASME B30.9-2025. These are strict removal criteria - the sling must come out of service immediately.
Wire rope slings must be removed from service with 6 randomly broken wires in one lay or 3 broken wires in one strand per ASME B30.9-2025. Kinking, birdcaging, heat damage above 400 degrees F, and corrosion also require immediate removal.