1.Steel wire ropes, slings and lifting appliances. The diameters of steel wire ropes have three specifications: 6×19, 6×37 and 6×61. For 6×19 steel wire ropes, they have a relatively large diameter and high strength, but poor flexibility, and are commonly used as guy ropes. The 6×37 and 6×61 steel wire ropes are used for the running ropes of pulley blocks and slings.
2. Slings are commonly known as hoisting ropes, rope sockets and slings. They are used to hang on the hook of a crane or the lower pulley of a pulley block to lift equipment components, and are most commonly used in large-scale hoisting operations.
3. The angle between the sling and the vertical line generally should be controlled between 30 degrees and 45 degrees. In special cases, it shall not be greater than 60 degrees. If more than two lifting points are used for hoisting, the angle between the sling of each lifting point and the horizontal plane should not be less than 60 degrees.
4. Selection requirements for slings. Steel wire rope slings are mainly according to parameters such as the weight of the lifted object, the diameter of the sling, the number of ropes, the stress angle, the nominal tensile strength of the steel wire rope and the safety factor.
5. Situations where steel wire rope slings shall not be used: The rope end is exposed at the prohibited hoisting mark and cannot be repaired; the rope strands are loose or separated and cannot be repaired. Steel wire ropes with broken wires, broken strands, extruded wires, extruded single-layer strand core steel wire ropes, and without nameplates shall not be used.
6. Safety factors of steel wire ropes. For drag ropes, the safety factor is greater than or equal to 3.5; for the running ropes of winches, the safety factor is greater than or equal to 5; for binding rope sockets, the safety factor is greater than or equal to 6; for hanging rope sockets, the safety factor is greater than or equal to 5; for manned baskets, the safety factor is greater than or equal to 14.
7. Usage requirements for lifting lugs and shackles. Before the equipment leaves the factory, the lifting lugs should be tested according to the design requirements, and a test report should be issued. After the equipment arrives at the site, the appearance quality of the lifting lugs should be inspected, and non-destructive testing should be carried out if necessary.
8. For the lifting lugs welded on site, the welded parts connected to the equipment should be subjected to surface penetration testing. After the equipment arrives at the site, the technicians should re-measure the welding position and dimensions of the lifting lugs.
9. Usage requirements for shackles. The shackles used in hoisting construction should be choose according to the rated load markings, and overloading is not allowed. Shackles without nameplates shall not be used. The surface of the shackle should be smooth, and there should be no defects such as burrs, cracks, sharp corners and interlayers. The method of welding shall not be used to repair the defects of the shackle. The shackle should be inspected visually before use. If there is permanent deformation or cracks, it should be scrapped. When using a shackle, it should only bear longitudinal tension.
10. Lifting beams or balance beams. When hoisting precision equipment and components, which are affected by the on-site environment or when multiple cranes are used for hoisting together, balance beams are generally used for hoisting.
11. The functions of the lifting beam are as follows:
1) Keep the lifted object balanced and avoid damaging the equipment by the slings.
2) Reduce the horizontal extrusion
force borne by the lifted object during hoisting to avoid damaging the equipment.
3) Shorten the height of the slings and reduce the hoisting height of the movable pulley.
4) When the stiffness of the component does not meet the requirements and multiple lifting points are required for hoisting and force-bearing, balance and distribute the loadof each lifting point.
5) Convert the lifting points. The lifting beam is used for the double-crane hoisting to complete the hoisting work of some equipment, mainly playing the roles of distributing the load of the cranes and converting the lifting points.
12. Design principles and usage of the lifting beam. The lifting beam should be designed according to the shape characteristics, dimensions, mass, performance of the hoisting machinery and the hoisting method of the lifted object. It can be made of seamless steel pipes, sections, steel plate box structures and their combinations. Its structural forms can be divided into solid web type and lattice type.
13. Usage requirements for the lifting beam. For the self-designed and manufactured lifting beam, its design drawings and verification calculation documents should be reviewed together with the hoisting construction technical plan, and it should be inspected and confirmed before use.
