How to choose the hook for the semi-portal crane?

Hook is one of the main parts of semi gantry crane, gantry crane hook the choice is due and manufacturing units, the certificate of approval of the technical documents, shall be put into use, otherwise should be upon examination, find out the performance qualified rear can use.

The hook surface should be clean, without stripping, acute Angle, hair crack, etc.

Do not use cast hooks.

In use, it shall be inspected, repaired and scrapped according to the relevant requirements of this procedure.

1, material

A. The hook material shall be of high quality low carbon structural steel or low carbon alloy steel;

B. The forging hook is generally used in GB 699-65 "high quality carbon structural steel steel number and general technical conditions";

C. The plate hook is generally used in GB 700-79 "ordinary carbon structural steel technical conditions" as stipulated in A3, C3 steel, or GB 1591-79 "low-alloy structural steel technical conditions" in 16Mn steel.

2. Check the hook.

A. The hoisting mechanism of the human drive bridge is used as A hook to test the load with 1.5 times of the rated load;

B. Hoist hoist with hoist hook and test load according to national standard.

C. After the lifting hook is removed to inspect the load, the increase of the opening degree should not exceed 0.25% of the original opening in the absence of any obvious defects and changes.

D. The hook should be able to support double inspection load reliably without falling off;

E. For the process mature, quality and stability, the use of common materials to make hooks, should check the hardness;

For each batch of hooks with the same furnace number, tonnage, and heat treatment of the same furnace, other mechanical properties besides the hardness are checked according to the standard.

Using the new material to make the hook, before the quality is not stable, to do 100% of the material machine mechanical performance test.

The inspection institution shall meet the relevant material standards.

Check qualified hooks.

The indelible mark should be made in the low stress area, and the certificate should be issued.

The contents are as follows:

A. Rated crane volume.

B, factory standard or factory name.

C. Inspection mark

D. Production number

3. Scrap standard of hook hook.

A, crack

B. 10% of the original size of the dangerous section;

C. The opening degree is 15% higher than the dimension.

D, torsional deformation of more than 10 °

E, dangerous section or hook neck produces plastic deformation.

F. When the plate hook liner wears out 50% of the original size, it shall be scrapped.

G, plate hook spindle wear to the original size of 5%, should discard the spindle.

H, the defects on the hook shall not be welded.