L68A1 Mast SectionIntroduction of several common tower crane defects
This article talks about the safety problems caused by the quality defects of the tower crane itself, and introduces several common tower crane defects. One, the flaw of the support pedestal one: the support pedestal fixing way is not reliable, in a tower lifting accident, because the tower crane crawler claw support pedestal and the sleeve welding bottom board tear, causes the crawler claw to turn up, the Jack Up Sleeve frame loses the support, causes the Tower Crane Sleeve frame together with the upper structure overturns the accident. The reason is that the thickness of the supporting plate of the tower crane is 25mm, while the thickness of the welding plate is only 8mm, and the strength of the welding plate is insufficient. Defect
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2: The welding quality of the support seat is poor, if the size of the weld is too small, the strength of the welding joint will decrease; the size of the weld is too large, the welding stress and deformation will increase; the welding surplus is too high, resulting in stress concentration, weakening the working performance of the structure. Welding crack is a dangerous welding defect. It is the origin of the fracture of welding structure. In addition, the bearing seat welding also easy to produce blowhole defects. 2. Claw Claw Defects Defect 1: Claw Strength is low, there is no large safety reserve, in fact, this kind of defect often occurs in the tower crane manufacturing stage, without authorization to reduce the original design standard requirements. It is suggested that the claw is the most important load-bearing structural component in the lifting process of tower crane, and the fracture often causes a serious safety accident of tower crane. The time Factor of safety should be raised to ensure a larger safety margin in use. Defect two: the material is not qualified, Claw Brittle fracture
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