1. Crane hook maintenance
(1) Disassemble and inspect the hook, shaft, beam, pulley, bearing, and clean and lubricate. The hook, beam, pulley shaft, and other parts must not have cracks, the threaded part should not be loose, the bearing should be intact, and the pulley should be rotated. If there are knife marks or cracks on the thread backing groove, it should be replaced;
(2) Check the wear of the dangerous section. If the wear of the dangerous section exceeds 10% of the original height, it should be replaced; Crane supplier
(3) Hook test. After overhaul, the hook should be tested and inspected. It should be suspended for 10 minutes at 1.25 times the rated load. The elastic opening of the hook mouth should not exceed 0.25% of the hook mouth size. There should be no deformation and cracks after unloading;
(4) Plate hook inspection. After the plate hook is riveted, the gap between the plates should not be greater than 0.3mm.
2. Crane wire rope maintenance
(1) Wire breakage inspection: If the number of broken wires in one lay exceeds 10% of the total number of wires, it should be scrapped according to the standard;
(2) Radial wear: If the radial wear of the wire exceeds 40% of the original diameter, the entire wire rope should be scrapped;
(3) Deformation inspection: If the wire rope diameter is reduced to 70% of the rope diameter, the rope core is exposed, and the strands are broken, it should be scrapped and replaced with a new wire rope;
(4) Wire rope lubrication: Before lubrication, clean it with a wire brush, kerosene, etc., and saturate it with wire rope grease (Q/SY1152-65) or synthetic graphite calcium-based lubricant (SYA1405-65).
3. Crane pulley maintenance
(1) Disassemble and clean the pulley and check for cracks. The pulley shaft shall not have cracks. The journal shall not be worn by 30% of the original diameter. The taper shall not exceed 5%. If it exceeds this value, it shall be replaced;
(2) Inspection of the pulley groove. Use a template to check the pulley groove shape. The radial wear shall not exceed 30% of the wall thickness, otherwise it shall be scrapped. If it does not exceed the standard, it can be repaired. After overhaul, use a template to check. The bottom and lateral clearance shall not be greater than 0.5mm, the deviation between the center line of the wheel groove and the center line of the pulley shall not be greater than 0.2mm, and the deviation of the rope groove center to the contour end face shall not be greater than 1mm;
(3) Inspection of the shaft hole. After overhaul, the shaft hole is allowed to have defects of no more than 0.25CM2, and the depth should not exceed 4mm;
(4) Assembly. After assembly, it should be able to be flexibly rotated by hand, and the lateral swing shall not exceed D/1000. D-nominal diameter of the pulley.
4. Crane drum maintenance
(1) Drum rope groove: if the rope groove is worn more than 2mm, it should be re-machined. After overhaul, the rope groove should meet the requirements of the drawing, but the drum wall thickness should not be less than 81% of the original thickness;
(2) Drum surface: there should be no cracks on the drum surface, there should be no obvious loss of roundness, and the pressure plate screws should not be loose;
(3) Drum shaft: there should be no cracks on the drum shaft. After overhaul, it should meet the requirements of the drawing. When the wear exceeds 5% of the nominal diameter, it should be replaced with a new part;
(4) Assembly and installation: the center line of the drum shaft should be parallel to the trolley frame support surface, and the deviation should not be greater than 1mm/m. After the drum is installed, the deviation of the center lines of the two shaft ends should not be greater than 0.15mm.
5. Crane wheel maintenance
(1) Wheel tread wear: if the wheel tread wear exceeds 15% of the original thickness, it should be replaced with a new part. If it does not exceed this value, it can be re-machined and heat-treated. The wheel diameter should be within the tolerance range, the surface quenching hardness should be HB300~500, and the quenching layer thickness should be greater than 20mm for wheels with a diameter greater than Φ400mm; when the diameter is less than Φ400mm, the quenching layer thickness should not be less than 15mm;
(2) The diameter deviation of two matching wheels should not exceed 0.1% of the nominal diameter for the driving wheel and 0.2% for the driven wheel. The diameter deviation of the electric hoist wheel should not exceed 1% of the nominal diameter and 0.2% for the driven wheel; the diameter deviation of the electric hoist wheel should not exceed 1% of the original diameter;
(3) Wheel rim wear, breakage and deformation: If the wheel rim wear reaches 50% of the original thickness or the breakage area exceeds 30mm2, it should be scrapped. If the wheel rim thickness bending deformation reaches 20% of the original thickness, it should be scrapped; Crane supplier
(4) Wheel cracks: If cracks are found in the wheel, it should be scrapped;
(5) Tread ovality: If the wheel tread ovality reaches 1mm, it should be scrapped;
(6) Wheel assembly: The installed wheel assembly should be able to be rotated flexibly by hand. Several wheels installed on the same balance frame should be in the same vertical plane, with an allowable deviation of 1mm.