How to determine whether the rigging accessories need to be replaced?

Lifting Hook

Crack

Judgment method: Visually inspect or use a 20x magnifying glass to check the dangerous section of the lifting hook. If cracks are found, regardless of their size, the hook should be replaced immediately.

Deformation

Judgment method: Measure the opening degree of the lifting hook with a ruler. The opening degree of a new hook has a specified size. When the opening degree of the hook increases by 10% compared to the original size, it should be scrapped and replaced. Meanwhile, observe the torsional deformation of the lifting hook. If the torsional deformation exceeds 10°, it also needs to be replaced.

Wear and tear

Judgment method: Measure the wear amount of the dangerous section of the hook. When the wear amount exceeds 10% of the original size, the lifting hook should be replaced. Precise measurement can be carried out through measuring tools such as calipers.

Lifting Links

Crack

Judgment method: Carefully inspect the body and the surface of the cross pin of the lifting links. If any cracks are found, stop using it immediately and replace the shackle. Cracks may occur in stress concentration areas such as the bending part and the threaded part of the shackles.

Deformation

Judgment method: Observe the shape of the lifting links. If there is obvious bending, twisting or other deformation, the shackle should be replaced. At the same time, measure the size of the lifting links. When the deformation exceeds a certain proportion of the original size (generally according to specific standards, such as 10%), it also needs to be scrapped.

Horizontal pin problem

Judgment method: Check whether the cross pin can rotate freely. If the cross pin does not rotate flexibly, gets stuck or the thread is damaged, the lifting links should be replaced. In addition, if the cross pins become bent or deformed, they should also be replaced in a timely manner.

Lifting Chain

Crack

Judgment method: Non-destructive testing methods such as magnetic particle testing and penetrant testing are adopted to conduct a comprehensive inspection of the lifting chain. If cracks are found on the surface or inside the lifting chain, the chain should be replaced immediately. For cracks visible to the naked eye, even greater attention should be paid.

Deformation

Judgment method: Measure the diameter and shape of the lifting chain. When the lifting chain undergoes plastic deformation, such as elongation, twisting, bending, etc., and the deformation exceeds 5% of the original size, the chain should be replaced. The deformation can be judged by comparing the size and shape of the new and old chain links.

Wear and tear

Judgment method: Use a caliper to measure the wear of the lifting chain. When the wear of the lifting chain exceeds 10% of the original diameter, the chain should be scrapped and replaced. Meanwhile, observe whether there are severe wear marks, grooves, etc. on the surface of the lifting chain.

Wire rope sling

Broken wire

Judgment method: When the number of broken wires in a wire rope slings reaches a certain level within one lay (the longitudinal distance between the corresponding two points when any strand of the wire rope rotates once around the core (360°)), it should be scrapped. For cross-twisted steel wire ropes, when the safety factor of the 6×19 structure (a common wire rope slings structure) is 6, the number of broken wires reaches 12. When the safety factor is 7, the number of broken wires reaches 14. The broken wires can be directly observed with the naked eye or inspected with a magnifying glass.

Wear and tear

Judgment method: Check whether there are severe wear marks on the surface of the wire rope slings, such as thinning of the steel wire or rough surface.

Rust

Judgment method: Inspect the rust condition on the surface of the wire rope slings. If there are severe pitting, pits, grooves, or loose outer wires on the surface without determining the number of wires, it should be scrapped immediately. For pitted pitting, its depth and area can be judged by visual inspection. For loose outer steel wires, you can gently shake the steel wire rope by hand to check.

Deformation

Judgment method: Observe whether the wire rope sling shows wavy, cage-like distortion, strand extrusion, wire extrusion, local increase in rope diameter, kinking, partial flattening, bending and other deformation conditions. If the above-mentioned deformation occurs, the steel wire rope should be scrapped immediately.