crane hook maintenance
When the hook of a crane is cracked or worn out, it must be replaced instead of repaired by welding. There are two reasons for this. First, it is difficult to reach the original quality standard by repairing welding. Second, the high temperature of repairing welding will reduce the temperature of the hook.
Crane hook is made of high-quality low-carbon killed steel or low-carbon alloy, which is annealed after forging. When the hook is subjected to impact load during operation, it can ensure sufficient strength and toughness of the hook assembly.
The hook head is made by forging and then heat treatment. Forging is a method in metal heat processing. The forging process is the process of metal structure refinement and metal fiber arrangement, while heat treatment is to eliminate internal stress and further improve the mechanical properties of the metal (it can be simply understood as making the internal structure of the metal more compact).
It is difficult to meet the quality standards of hook repair welding. Repair welding is the whole process of partial melting, fusion and solidification of metal. During repair welding, due to heat conduction, part of the base metal of the hook matrix near the repair welding is heated and cooled to varying degrees, just like a heat treatment of this part, which changes the structure and performance of this part. Most welding is for the worn concave parts of the hook, and the concave is in the same line as the vertical dangerous section. Repair welding destroys the metal structure refinement and metal fiber sequence of the hook, destroys the toughness of the hook, and thus reduces the performance of the hook.
Generally speaking, daily inspection and maintenance of hooks include the following:
(1) Clean the crane hook block body with a non-corrosive organic solvent, wipe it dry and inspect it with a magnifying glass. If cracks are found, replace it immediately and do not perform repair welding.
(2) Check the hook opening and the amount of wear on the dangerous section.
(3) Check whether the pulley groove and rim are evenly worn, whether the wire rope matches the groove, and whether the pulley is loose or shaking.
(4) Ensure that the rotating part of the hook rotates freely and the gap is not too large. If it is difficult to rotate or stuck, check whether the bearing or sleeve is damaged or lubricated insufficiently.
(5) Check the overload damage of the main hook.
(6) Check the hook guard plate, crossbeam and other parts. If the guard plate is severely worn, it can be repaired by welding and re-boring. If a new part is replaced, it is necessary to ensure that the mechanical properties of the material meet the requirements.
(7) Check the anti-unhooking device.
Glory Rail is based on rail systems. At the same time, we expanded the research, development, and production of crane hooks. Provide different types of lifting hook products for various cranes and port machinery equipment.
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