Are there any technical requirements for using a hook?

Hooks are widely classified, generally including: shackles, rings, rings, pear-shaped rings, long rings, combined rings, S hooks, nose hooks, American hooks, horn hooks, eye-shaped hooks, eye-shaped screws with insurance cards, chain shackles, with unique, novel, high-quality, safe characteristics. The hook is the most common spreader in lifting machinery.

The hook is often suspended on the wire rope of the lifting mechanism with the help of components such as pulley blocks.

General technical requirements for hooks.

1. The purchase of hooks should be used only with technical documents such as the manufacturer's certificate; Important departments purchase hooks such as: railways, ports, etc., and the hooks need to be strictly inspected (flaw detection) before leaving the factory.

2. The hook shall not have defects that affect the safety performance; Hook defects shall not be welded; The surface of the hook should be smooth, and there should be no cracks, folding, acute angles, burrs, peeling, overburning and other defects.

3. Two appropriate positions can be selected at the shortest distance of the hook opening to print the sign that is not easy to wear, and the distance of the sign can be measured as the basis for detecting whether the opening degree changes in use.

4. The hook material can be made of 20 high-quality carbon steel or special materials for the hook, such as DG20MN and DG34CRMO, and it is strictly forbidden to use casting hooks. The material of the plate hook is generally A3, C3 ordinary carbon steel, or 16MN low alloy steel.

5. The technical conditions of the self-made hook should meet the provisions of GB (new standard.

6. The longitudinal axis of the plate hook hook must be located in the rolling direction of the steel plate, and the hook is not allowed to be spliced.

7. The plate hook hook piece should be riveted with countersunk rivets, and the high-stress bending parts in contact between the plate hook and the lifting object shall not be connected with rivets.

8. Fully enclosed welding is not allowed between the plate hook laminations, and only intermittent welding is allowed.

9. The hook that has been overloaded should be scrapped.

The hook is the main part of the lifting machinery, and its material, manufacturing process, quality maintenance and inspection and other links are negligent in management, which will directly cause accidents. Therefore, the hook must be strictly controlled by the material, inspection and scrapping standards.

Material: The hook material must be made of high-quality low-carbon calm steel or low-carbon alloy, and the plate steel is generally used in GB700-79 "Technical Conditions for Ordinary Carbon Structural Steel" specified in the A3 and C3 steel 16MN steel. Hooks are divided into single hooks and double hooks according to their shape; According to the manufacturing method, it is divided into forged hook and laminated hook.

The single hook is simple to manufacture and easy to use, but the force is not good, and it is mostly used in working occasions with a lifting capacity of less than 80 tons; Symmetrical double hooks are often used for large lifting weights. The laminated hook is riveted by several pieces of cut and formed steel plates, and the whole hook will not be damaged when individual plates are cracked, and the safety is better, but the self-weight is larger, and it is mostly used in the crane with large lifting capacity or lifting the barrel of molten steel. The hook is often impacted during the operation and must be made of high-quality carbon steel with good toughness.

The hook is heated to 1250 many times in the forging process, and is often in a local forging state, so its rod often produces coarse grains. In order to ensure the mechanical properties of the hook, it is necessary to use an appropriate heat treatment process to eliminate the coarse grains in the rod section. The grade of the hook depends on the mechanical properties of the finished hook.

Rated lifting capacity and grade, with the value of rated lifting capacity and test load, four hook grades are specified, which are represented by the letters M, P, S, T. The basic design load of the hook is equal to the test load (fe). M, P, S, T four grades of hooks on steel requirements:

1) The steel should be made of open-hearth, electric furnace and oxygen top blowing converter;

2) The steel should be a calm steel, with good malleability, and can meet the mechanical properties specified in the standard after appropriate heat treatment;

3) When the steel is tested according to YB T5148, it should reach the grade of austenite No. 5 grain size or finer.

What should I pay attention to when using the hook?

The precautions that should be paid attention to when using the hook are:

1. The surface of the hook and ring should be smooth, and after 1 to 3 years of use, it should be inspected once.

2. When it is found that the wear degree of the hook is more than 10% on the dangerous section, the load should be reduced. Load test of the hook: it will be a weight rated at 125% of its weight, suspended for 10 minutes, after unloading, the hook mouth will be measured, if there is permanent deformation and cracks, the load should be renewed or reduced.

3. The hook needs to be updated when one of the following situations occurs:

1) Observe the surface with a 20x magnifying glass, and there are cracks or cracks.

2) Permanent deformation caused by load test.

3) There are deformations and cracks in the hook tail and thread parts.

4) There are fatigue cracks at the corners of the transition between the threaded part and the unthreaded part of the hook tail.

The hook should be fitted with a safety device to prevent decoupling.

Hooks are divided into single hooks and double hooks. The single hook is more convenient to manufacture and use, and is used for smaller lifting capacity; When the lifting capacity is large, in order not to make the hook too heavy, double hooks are mostly used. The cross-sectional shape of the hook body (curved part) of the hook body is as follows:

Circles, rectangles, trapezoids, T-shapes, etc. The inspection of various hooks focuses on the inspection of forging hooks, the inspection of plate hooks and the load test of hooks.

The anti-decoupling device on the heavy machine hook requires that all tonnages must be available.

This regulation has long been out.

It has only been implemented in earnest in recent years.

At present, the anti-decoupling device is in the market, and there are still some hooks of small factories and the previous inventory of large factories without anti-decoupling devices.

If you want to buy a regular product, there is also a separate anti-decoupling device on the market, if your hook does not have a mounting hole, do not weld the installation ear.

Keep in mind that the hook is not allowed to be welded, and it is directly judged to be unqualified.

Tower crane hook hook requirements envy shed hello, hook is not installed wire rope anti-decoupling device or does not meet the specifications deduct 10 points hook wear, deformation to reach the scrap standard deduction 10 points pulley, drum is not installed wire rope anti-decoupling device brother excitation or does not meet the requirements of the specification deduct 4 points deducted for pulley and drum wear to reach the scrap standard deduction 10 points wire rope wear, deformation, rust to meet the lead sail scrap standard deduction 10 points wire rope specifications, fixing, winding does not meet the instructions and specifications deduct 5 10. The hook of the wire rope anti-detachment device should be equipped with a device to prevent the wire rope from being unhooked. JGJ196 hook scrapped standard hook is strictly forbidden to repair welding, one of the following circumstances should be scrapped: 1

There are cracks on the surface 2The wear of the section at the lanyard exceeds 10% of the original height3Dangerous sections such as hook tail and thread parts and hook bars have permanent deformation4

According to the requirements of relevant crane standards, ordinary cranes are checked every two years. Cranes that have been overhauled, newly installed and re-selected should be inspected prior to delivery. For cranes that have been idle for more than one year, before re-use, in a storm.

and after a major accident, cranes that may cause damage to strength, stiffness, component stability, and institutional importance should be inspected before use.

2) Regular inspections should be carried out according to the heavy workload and harsh environment, but not less than once a month. Generally, it should include: the technical performance of the crane during normal operation:

All protective devices; leaks and operating conditions of pipelines, tanks, vessel valves, pumps, hydraulic or pneumatic other components; hooks, hook nuts and anti-loosening devices; braking performance and component wear; Wire rope wear and tail end fixation; wear, deformation and elongation of the chain; Chains, wire ropes and accessories.

Periodic inspections should be carried out according to the heavy workload and harsh environment, and the inspection cycle should be determined, but not less than once a year. In general, it should include the content of the second periodic inspection; Deformation, cracks and corrosion of metal structures. Wear, cracks and deformation of the main parts of the connection such as welds, rivets, bolts, etc.; reliability and accuracy of the indication device; Dynamical system.

and manipulators, etc.

The most important thing for the hook used in the crane is to test the strength that the hook can bear, and generally take the hook itself to test the maximum load that the hook can bear on the tensile testing machine....

Generally, fatigue crack flaw detection generally uses magnetic particle or penetration, and non-destructive testing is a commonly used detection method for Facai, which can find small defects and fine cracks on the surface of hooks and spreaders, and can quickly and clearly find the problem.

The hook is an important part of the lifting machinery, he is stressed in a complex condition, in addition to bearing the weight of heavy objects, but also to bear the impact load generated during lifting and braking, and the hook that has been used for a long time will inevitably produce cracks.

The hook is an important detection component for crane safety testing, and hook crack detection is an important testing item for the safety testing of lifting machinery.