Common sense about construction machinery and equipment scrapping standards for construction machinery and equipment
1. Tower crane: focus on checking the inspection report of the crane, and check various types on site Restrictions, limit devices and safety devices, whether the operating and command personnel of the tower crane hold valid certificates for work.
2 Gantry: Focus on checking whether the installation of the frame is stable and reliable, whether the limit safety device is complete and effective, whether the braking is sensitive and reliable, whether the broken rope protection is effective, and the cable wind rope must use a steel wire rope of more than 9MM Reliable anchorage, whether the hanging basket has a safety door and side baffles, whether the floor unloading platform is tightly protected, whether the lightning rod and grounding are reliable.
3. Small and medium-sized machines: Focus on checking whether all kinds of protective devices are complete and effective, the operating status of the transmission part, whether there is grounding, zero protection, etc.
What basic requirements must the hook of the lifting machinery meet?
The material of the hook is required to have high strength and plastic toughness, and there is no risk of sudden breakage. At present, hooks are widely used in mild steel and alloy steel.
What are the regulations on the scrapping of wire ropes in the “Safety Regulations for Hoisting Machinery”?
Judge whether the steel wire rope should be continued to be used or scrapped, mainly based on the degree of broken wires of the steel rope and some other conditions.
The scrapping standards are as follows:
(1) The number of broken wires in the lifting machinery wire rope within one twist pitch reaches 10% of the total number of wires in the wire rope. For example, if the rope is 6 × 19 = 114 wires, it should be scrapped and replaced when the number of broken wires reaches 12. For example, if the rope is 6 × 37 = 222 wires, when the number of broken wires reaches 22, it should be scrapped and replaced. For steel wire ropes composed of thick and thin wires, the number of broken wires is calculated as one thin wire and one thick wire as 1.7.
(2) If the radial wear or corrosion of the steel wire exceeds 40% of the original diameter, it should be scrapped. When it is less than 40%, the number of broken wires can be reduced and scrapped according to regulations.
(3) The number of scrap wires for wire ropes used by lifting machinery to lift hot metal or dangerous goods shall be half of the scrap standard for wire ropes used in general cranes.
(4) For wire ropes that comply with ISO2408 For structural steel wire ropes stipulated in the standard “Characteristics of General Purpose Steel Wire Ropes”, the number of broken wires to be scrapped should be the number specified in GB5972-86.
(5) The entire rope strand should be scrapped if it breaks.
(6) When the diameter of the wire rope is reduced by 7% or more relative to the nominal diameter, the wire rope should be scrapped even if no broken wire is found.
(7) The exposed hemp core should be scrapped.
(8) From China Hoisting Machinery Network, the steel wire rope has obvious corrosion and should be scrapped.
(9) Part of the outer steel wire is stretched into a cage shape and should be scrapped
(10) Compare the typical examples of possible occurrences of steel wire ropes in GB5972-86. Those with the same damage as in the picture should be scrapped.
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