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The Hook Has Enough Strength And Stiffness Oct 19, 2017


Safety Requirements for Hooks

The hook should have enough strength and rigidity, so the material and processing of the hook have strict requirements, not to use the casting hook, not to use the impact of low toughness material production. The hook is divided into forged hook and laminated riveting board hook. Forged hooks are usually made of 20th # High quality low-carbon steel with good plasticity and not easy to produce brittle, Lifting Hooks and then annealed by annealing, and the plate hook is made of 20th steel, Q235, 16MN steel plate riveting.

The hook should be flexible, fixed nut positioning bolts, opening pins, and so on must be tightly finished, and the hook surface should be smooth, no stripping, acute, Lifting Hooks burr and other defects. Any defects on the hook shall not be welded, because the welding temperature will cause the material mechanical properties and metal microstructure changes, increase the brittleness of the material.

Safety inspection and security check of hook

1. The load test of the hook should be used for the new hook and the hook used for a period of time should be load tested to 1 of the rated load. 5 times times as the test load, Lifting Hooks load suspension time is not less than 10 minutes, after unloading should not be permanent deformation.

For the use of a time hook, you can also do load test, determine the use of load. Hook use after a period of time, because of the role of wire rope, often make the hook surface hardening. In order to prevent this surface hardening, it can be annealed every six months to one year, but the temperature must be controlled according to the material, otherwise it will make the metal grains of the hook thicker and affect the service life. Lifting Hooks For the forged hooks made of No. 20th steel, the annealing temperature can be controlled in 500℃~600℃ and cooled slowly after heat preservation so that the microstructure of the steel will not change.

2. Safety inspection of hooks: The hook shall be inspected at least once a year for the frequent use of the hook at least once per quarter. Before the test, the application of kerosene cleaning hook body, with 20 times times magnifying glass to check the dangerous section, no cracks, plastic deformation, rivet loosening and so on. The inspection of the hook, the processing surface should be coated with anti-rust oil, Lifting Hooks non-machined surface should be coated with antirust paint, and should be in the low stress area to make the mark is not easy to wear off.

3. Safety check of the hook: the inspection period should be determined according to the heavy workload and the bad environment, but not less than once a month. Main check the hook has no crack, Lifting Hooks deformation and hook nut and loose device, check the bushing, mandrel, small hole, ear and the wear of its fasteners. The hook assembly must be repaired at least once a quarter and cleaned and lubricated.

Scrap Standard for Hooks

1. Crack: The main point is the danger section of the Hook Bottom and the section of the hook-tail thread part retract groove, Lifting Hooks if there is crack should be scrapped.

2. Because the friction of wire rope often produces groove, according to regulations, the dangerous section wear up to 10% of the original size should be scrapped. Do not exceed the standard, can continue to use or reduce the use of load, do not allow the use of welding rods before using.

3. The opening degree is 15% higher than the original size: The emphasis is on the bending hook of the self-made steel bar, which can cause overload and increase the opening degree.

4. Torsional deformation over 10 °.

5. The dangerous section or the hook neck produces plastic deformation.

6. When the plate hook bushing wears up to 50% of the original size, Lifting Hooks the liner should be scrapped.

7. When the mandrel of the board is worn up to 5% of the original size, Lifting Hooks the mandrel should be scrapped. 

8. The thread part of the hook is corroded.