L46A1 Mast Section The main load-bearing structural parts of tower crane shall be scrapped if they meet these conditions
1. When the main bearing structure of the tower crane loses its overall stability and cannot be repaired.
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2. The calculated stress of the main load-bearing structural parts of tower crane increases due to corrosion, when it exceeds 15% of the original calculated stress. For those without calculation conditions, when the corrosion depth reaches 10% of the original thickness.
3. When the main load-bearing structure of the tower crane can not eliminate the influence of cracks.
(1) All assemblies, parts, accessories and accessories shall be complete.
(2) The pre tightening force of bolt or rivet connection of metal structure shall conform to the specification.
(3) The main working performance of the whole machine shall reach the rated index.
4. All lubricating devices shall be complete and well lubricated.
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5. The hoisting machinery specified in the regulations on safety supervision of special equipment can only be used after passing the inspection by a qualified inspection and testing institution.
