Analysis of the hottest maintenance case of port c

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Analysis of a port crane maintenance case

with the continuous increase of the crane market and its wider application, crane repair problems, especially those related to the repair or reinforcement of structural parts, have attracted more attention. The following is an example of Qinhuangdao special equipment supervision and Inspection Institute inspecting the chassis structural parts of a port v133t port crane reinforced at the beginning of 2007, to introduce the relevant aspects

the reinforcement effect of the mechanism is mainly determined by the reinforcement scheme, the quality of the selected material, the welding process and the strength inspection

in terms of the reinforcement scheme, according to the specific stress conditions and stress concentration characteristics of the chassis:

the chassis is a beam structure, mainly subject to bending stress, and the stress is concentrated at the position where the far end of the outrigger is combined with the center rotation, and the cross section of the chassis is a box structure. According to these actual conditions, and in combination with the construction requirements, we decided to adopt the scheme that we can consult us about what we don't understand. We can stick the opposite plate and the horizontal plate respectively for reinforcement, and weld the two sticking plates into one with a cable-stayed plate. In this way, the three plates form a stable tripod structure. Through theoretical calculation, the strength is increased by more than 15%, which meets the actual use requirements

in terms of the selected material, we first identify the base metal, analyze the content of main chemical elements and various mechanical property parameters, and require the selected material: the chemical composition is close to the base metal to ensure the welding effect; The mechanical properties exceed the base metal to ensure the strength requirements. After selecting the new material of made in China 2025, which was officially issued by the State Council in 2015, the base metal and the new material were sampled and welded together for damage test. The result was that the base metal was broken, indicating that the strength of the new material and the welded part was greater than that of the base metal, ensuring the construction quality and strength requirements

in terms of welding process, we mainly require it from six aspects: parent body cleaning and preheating, electrode drying, processing reinforcing plate, welding machine, welding construction engineering, multiple experimental curve sequences of pipe materials and post welding insulation, so as to ensure the construction quality

in terms of strength inspection, it is mainly to check that all welds shall be free of missing welding and burning through, and the welds shall be free of cracks and incomplete fusion defects. The welding of the main board is a class I weld, and it is expected to use nanoparticles to strengthen the properties of modified plastics, and some welds are class II welds, and the weld bead shall be inspected for welding defects (nondestructive testing). After the welds meet the above four requirements, the whole vehicle shall be hoisted for test, and the structural parts shall be stress tested. The percentage of strength improvement of chassis structural parts shall be judged according to the test strain method, and then compared with the actual requirement of 15%, so as to draw a conclusion whether the construction is qualified

structural member reinforcement is a highly demanding and important engineering project, and management and supervision must be strengthened in all links to ensure that everything is safe. (Wang Dajun)

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