Wire Rope Inspection and Replacement Flashcards

A mobile crane's load hoist wire rope is 6×36 IWRC construction. During inspection, you find 4 broken wires in one strand within a single lay length. Per ASME B30.5, what is the correct disposition of this rope?

Answer: The rope must be removed from service immediately

ASME B30.5 requires removal from service if there are 3 or more broken wires in one strand within one lay length, regardless of the total broken wire count across the rope. Four broken wires concentrated in a single strand triggers immediate removal — the strand-specific criterion is more restrictive than the overall 6-in-one-lay rule.

When inspecting a wire rope operating over a sheave with a D/d ratio of 18:1, which type of wire rope fatigue failure is MOST likely to manifest first, and where should the inspector focus attention?

Answer: Valley wire fatigue between strands at the contact points with the sheave groove, driven by inter-strand pressure

At a D/d ratio of 18:1, which is below the recommended minimum for many rope constructions, the predominant failure mode is valley wire fatigue — the inner wires caught between strands experience repeated compressive loading as the rope wraps the sheave. This manifests as subsurface breaks invisible during external inspection, making the contact-point geometry (valley vs. crown) the critical distinction.

A 1-inch diameter wire rope shows a measured diameter reduction of 1/16 inch at a localized section. The rope has no visible broken wires at that section. What is the CORRECT action per ASME B30.5?

Answer: The rope must be removed from service because a localized diameter reduction of 1/16 inch on a 1-inch rope exceeds the allowable 3/64-inch reduction

ASME B30.5 requires removal when a localized diameter reduction exceeds 3/64 inch (approximately 0.047 inch) regardless of rope diameter. A 1/16-inch (0.0625-inch) reduction exceeds this absolute threshold. Note that this is an absolute measurement criterion, not a percentage — the 6.25% figure in option B uses a percentage-based threshold that does not apply here. Localized diameter loss indicates internal core failure or severe wear and is a definitive removal criterion.

During a frequent inspection of a tower crane's pendant (standing) rope, an inspector finds 2 broken wires within one lay length with no other deficiencies. Per ASME B30.3 criteria for standing ropes, what is the required action?

Answer: The rope must be removed from service immediately because the removal criterion for standing ropes is 2 broken wires per lay length

ASME B30.3 applies a much more stringent removal criterion to standing (non-running) ropes than to running ropes. For standing wire ropes, the removal criterion is 2 broken wires within one lay length — far lower than the 6-wire threshold applied to running ropes under ASME B30.5. Because pendant and standing ropes are always under tension and rarely flex, any wire break indicates serious localized stress concentration requiring immediate removal.

A wire rope is being removed from a hoist drum after service. The inspector notices the outer wires on the rope show a 'birdcaging' pattern only in the sections that were never in contact with the drum. What is the MOST likely cause?

Answer: The rope was subjected to sudden release of tension (shock unloading) while under high load, causing the strands to spring outward

Birdcaging that occurs specifically in free-span sections (not drum-contact zones) is a classic signature of shock unloading — a sudden release of tension while the rope is under high dynamic load. The rapid tension drop allows the outer strands, which were compressed radially under tension, to spring outward and lose their helical seating. This is distinct from overloading (which compresses, not expands) and from reverse bending (which creates localized deformation at the bend point, not in free spans).

When installing a new wire rope using the 'end-for-end' reversal method to equalize wear, which condition would make this practice UNSAFE and require rope replacement instead?

Answer: The rope exhibits heat discoloration (straw to blue coloring) at the originally-top end that was closest to the drum

Heat discoloration (straw, brown, or blue coloring) is a definitive rejection criterion regardless of where it appears, because it indicates the rope reached temperatures that alter the metallurgical properties of the wire — reducing ductility and fatigue resistance permanently. End-for-end reversal is designed to equalize mechanical wear, but it cannot reverse heat damage. Installing the heat-affected end into the higher-stress position on the drum would compound an already-compromised rope. Broken wires on the light end (option B) use the wrong threshold — 2 per lay is removal; but heat damage is categorically non-reversible and overrides the reversal strategy.