As we all know, the steel beam is an important part of the Double Beam crane. It determines how much load-bearing the overhead crane and gantry crane can carry. So what faults will the steel beam of the double-beam crane appear usually? What are the forms of damage?
Double Beam Overhead Crane
Double Beam Crane Main Steel Beam Surface corrosion
Surface corrosion (interpretation: refers to decay, disappearance, erosion, etc.). The working environment of the Double Beam crane is harsh. It usually works in gas dust (form: solid particles) containing acid-base corrosion (interpretation: refers to decay, disappearance, erosion, etc.). In addition, the collision during operation and the natural aging and peeling of the anti-rust coating make the surface lose its protection.
In addition, maintenance work of the Double Beam crane is not timely, resulting in partial corrosion and oxygenation, varying degrees of surface rust, reducing the strength of steel beams, and making steel knots for a long time. Structural deformation, which is also a common fault in the main girder of a double-beam crane.
Double Beam Crane Main Steel Beam Cracks
Practice has proved that although crane main girder cracks do not necessarily lead to fractures, it is very important to find and deal with them in time. Even if it is not repaired in time, long-term work is often the initial stage of cracks, especially the transition period and dangerous cracks. Generally speaking, cracks mainly occur in the welding part and the part where the stress is concentrated.
Double Beam Crane Main Steel Beam Deformation
The deformation of Double Beam overhead crane and Double Beam gantry crane includes partial bending (Bend) deformation, twisting and eccentricity. According to the metal structure inspection requirements, the straightness tolerance of the rod along the longitudinal axis is 1/750. The Double Beam crane deformation of the main chord in use should not be more than 3 permille; -5 permille;; the deformation of the web should not be more than 2-4mm; the hole distance error of the rod connecting bolt (composition: head and screw) should not exceed the assembly (assemble) 1/2 of the gap; and the roundness error of the screw hole does not exceed 1/2 of the assembly gap; when it exceeds the above range, it is deemed to be deformed.
Double Beam Crane Steel Beam Deformation Reasons
Double Beam Gantry Crane
The reasons of Double Beam crane steel beam deformation are as follows:
The local bending deformation of the Double Beam crane steel beam is caused by collision and impact.
Due to the loosening of the connecting bolts (composition: head and screw), the bolt holes are ground into an ellipse, resulting in eccentricity of the arm and additional bending moment. (3) Accidental collision and deformation of steel beams are caused by wrong actions. If the operating mechanism (organization) fails, the boom will reverse uncontrollably, and a collision with the tower will cause serious deformation.
Long-term overload causes the steel beam to yield deformation (permanent deformation). In addition to steel girder failures, there are other failures of Double Beam Cranes that need to be paid special attention to. For details, please refer to common failures and troubleshooting of general Double Beam bridge cranes.
What are the precautions for the routine inspection of Double Beam Cranes?
1. The limit switch, height limiter, and each interlocking mechanism are formed during lifting. The performance is normal, safe and reliable.
2. Requirements for main components: The opening size is less than 15% of the original size, and the torsion deformation is less than 10%; the wear of the plate hook bushing is less than 50% of the original size, and the wear of the plate hook mandrel should be less than 5% without peeling or repairing. Welding, burrs, hook hangers, pulleys have no obvious defects
3. The amount of wear and corrosion on the surface of the steel wire rope should be less than 40% of the diameter of the steel wire, and the wire should be less than 10% of the total number of wires at a certain distance. Burning, twisting of dead corners, annealing phenomenon
4. No cracks in the drum, no loose connection and fixation; the wall wear of the drum is less than 20% of the original wall thickness; the safety roll is not less than 2 turns, the diameter ratio of the drum and the wire rope should meet the requirements, and the balance wheel should be in good condition.
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