Scrap standards for metal structures of electric single-girder cranes

The metal structure bridge of the electric single-beam crane is composed of a main beam and an end beam. The main beam is composed of U-shaped channel steel and I-shaped steel, and the end beam is made of U-shaped channel steel. The metal mechanism bridges of the LD electric single-beam crane are all welded. Our factory reminds everyone: in order to ensure the safe use of the electric single-beam crane, when the metal structure reaches the scrap standard, it will be scrapped in time and replaced with new equipment. The specific scrap requirements are as follows:

1.  The main load-bearing components, such as main beams, end beams, etc., should be scrapped when they lose their overall stability.
2.  When the main load-bearing components of the crane, such as the main beam, end beam, trolley frame, and spreader beam, undergo obvious corrosion, inspection, measurement and calculation shall be carried out. When the calculated carrying capacity cannot reach the rated carrying capacity, maintenance shall be carried out to make it meet the requirements for use, or modification shall be carried out to reduce the rated lifting capacity, otherwise it shall be scrapped.
3.  Crane main beams, end beams, trolley frames, spreader beams and other main load-bearing components should stop using when cracks occur. Only the impact of the cracks and the measures to prevent the cracks from continuing to grow can be used for safety assessment and confirmation, or After replacing the structural parts with cracks, they can continue to be used, otherwise they should be scrapped.
4.  When the main load-bearing components of the crane, such as the main beam, end beam, trolley frame, and spreader beam, are plastically deformed and the working mechanism cannot operate normally and safely, if it cannot be repaired, it shall be scrapped.
5.  When the trolley of the single-beam crane is located in the middle of the span for the rated load, the deflection value of the main beam in the middle of the span is below the horizontal line and reaches 1/700 of the span. If it cannot be repaired, it should be scrapped and updated.

Features of metal structure:

1.  The materials used in the main metal structures (main beams, end beams) have material reports and corresponding certificates of conformity.
2.  The manufacturing, welding and inspection of metal structures are carried out in accordance with national standards. Important force-bearing butt welds adopt double-sided groove welding process, and conduct visual inspection and non-destructive inspection according to regulations. All welders hold corresponding grade certificates.
3.  The main beam of all cranes adopts the whole plate without butt joint process, and the butt welding seam of the main beam steel plate is eliminated, which eliminates the hidden danger of the steel plate butt welding volume. (Steel plate butt welding is the most important welding and the part with the most hidden quality problems)
4.  All plates are automatically cut by a CNC cutting machine, and the arch of the main beam is preset to avoid the problem of downward deflection of the traditional fire-baked main beam.
5.  The steel surface is shot blasted, and its surface roughness reaches the Sa2.5 level in GB8923 "Steel surface treatment registration and rust removal grade before painting", which improves the paint adhesion and does not peel off the paint, ensuring the integrity of the single beam crane Long-term beautiful machine
6.  The longitudinal waist welding seam of the main beam adopts domestic advanced automatic special machine ambush welding, which is beautiful in shape and guarantees the welding quality.
7.  The crossbeam of the cart is made of rectangular tube as a whole, without splicing, no welding seam, beautiful appearance, sturdy and durable.
8.  All wheels are installed by boring type to avoid wheel treads not on the same horizontal plane and improve wheel running accuracy.

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