The bolt of walking beam track in hot plate branch

  • Detail

Use case of walking beam track bolt in hot plate branch of No. 1 steel rolling plant of Masteel

I. workshop: continuous rolling workshop of hot plate branch of No. 1 steel rolling plant of Masteel

II. Application position: walking beam track

III. application specification: TM20 × 120

IV. time of use: April 15, 2006

v. time of report: December 5, 2006

VI. reason of use:

the walking beam equipment is a mechanical equipment for transmission, which is used to transport the finished steel coil to the designated location of the finished product warehouse. Its characteristic is that it has a large impact load. The working characteristics of walking beam determine that it has high requirements for fastener locking. The looseness of the guide rail will lead to the failure of the equipment to work normally, the deviation of the steel coil transportation position, and serious damage to the equipment, which will lead to the shutdown of the whole production line

generally, the guide rail of the walking beam is fastened with ordinary high-strength bolts, but because the walking beam works in a stepping manner, the impact load is large, and the bolts often loosen. After the bolt is loosened, the friction force of the bolt along the step direction disappears, and the bolt is mainly subject to shear force, and the bolt will be cut under the impact of the step direction. In this way, the working condition of the equipment deteriorates, which is easy to cause equipment damage

maintenance mainly adopts the methods of daily patrol inspection and planned maintenance. Spot inspectors patrol every day and tighten the bolts immediately if they are loose. In addition, maintenance is arranged every two weeks to tighten all the bolts and replace some damaged bolts while stabilizing their position in the electronic and electrical industry. Because the walking beam track is below the ground, the maintenance is very inconvenient. The method of spot inspection and planned maintenance still can't solve the problem. The bolts are still stretched and bent during the working process. We need to carry out spot inspection, color testing, deformation, and even cutting before mass production. Therefore, solving the problem of bolt looseness has become the primary problem whether the walking beam equipment can work normally

first of all, the bolt installation tracking process

after contacting the workshop point inspection operator and introducing the unique structural locking effect of Down's threaded fasteners, the operator introduced the specific personnel responsible for the maintenance of the walking beam. The maintenance personnel reported that the fixed bolts on the walking beam have always been a difficult problem to solve. The bolts are often loosened, resulting in the irregular maintenance time of the walking beam, which affects the normal maintenance time arranged each time. The walking beam guide rail is a conveying track located below the ground. The usual maintenance is underground operation. The environment is relatively poor, the space is small, the light is dark, and the temperature is high, which brings inconvenience to the maintenance personnel. Moreover, it takes 1 ~ 2 people to tighten the loose bolts every time, and the tightening time is up to 4 ~ 6 hours. In this way, the maintenance of the fixed bolts of the whole walking beam guide rail causes great inconvenience to the workers, and also costs a lot of manpower Material resources

after discussing with the workshop foreman and the person in charge of specific equipment, it is determined that the bolts on one line of the walking beam guide rail will be replaced on April 1

because the hot plate maintenance is undertaken by the outsourcing workers, who are not familiar with the characteristics of Down's threaded fasteners, and our company's on-site service personnel are not on the installation site, the installation torque of the installer is too large, resulting in two bolts being twisted, and the field reflects that our company's bolts cannot be used, the equipment management personnel of the hot plate factory decided to stop using our company's products and notify our company of the situation

our company rushed to the site immediately after receiving the notice to understand the situation, took back the remaining bolts for testing, and confirmed that there was no problem with the bolt quality

our company once again discussed with the operator and equipment management personnel, emphasizing that the pre tightening torque of Down's threaded fasteners is lower than that of ordinary bolts, and the pre tightening force of the locknut is greater than that of the fastening nut. It is required that the pre tightening force of the fastening nut should be 80% of the pre tightening force of the locknut. It is determined that the torque of the fastening nut is 150kn · m, and the torque of the locking nut is 180 kn · M. Through negotiation, it is determined that the equipment management personnel will install it, and our on-site service personnel will guide it on site, and use a torque wrench to control the torque

during the second trial installation and replacement, our company arrived at the replacement site within a predetermined time, and gave guidance and explanation to the installation personnel before the replacement. After more than two hours, one of the lines of the walking beam guide rail was replaced, and a torque wrench was used during the installation, which gave the maintenance personnel a preliminary understanding during the installation and achieved accurate and standardized installation

VIII use effect:

1. The bolt preload was checked after 7 days of use, and the bolt preload was basically normal

2. No looseness is observed during the normal maintenance time every half month

3. it has not loosened since use, and it is in a maintenance free state

IX pictures of on-site use:

1. Before replacement, ordinary high-strength bolts are often loosened, resulting in the displacement of special-shaped gaskets, which cannot meet the pre tightening requirements of equipment operation and brings great inconvenience to production

pictures of using ordinary bolts

pictures of using Down's bolts

X. comments of workshop equipment head and equipment maintenance personnel

1. Wang Feng (leader of equipment spot inspection team): the use of ordinary bolts often causes loosening and fracture. The maintenance method adopted is routine inspection and fastening by spot inspection. In addition, an overhaul plan is arranged every half a month to tighten all the loose bolts used. Since the use of Down's thread fastening bolts, the walking beam has not been loosened. Now, maintenance personnel are no longer arranged to tighten the loose bolts during each maintenance, which saves labor and reduces the maintenance cost, thus improving the working state of the walking beam and alleviating the pressure that affects production and each maintenance due to the looseness of the guide rail of the walking beam

2. Xia Ji'an (Deputy monitor of equipment spot inspection team): the anti loosening effect of Tang's threaded fasteners is really amazing. In the past, ordinary high-strength bolts were used, and the bolts were often loose and broken. Fastening the bolts became the most troublesome thing in maintenance. In addition to checking the fastening bolts every day, the maintenance should be arranged every half a month, which brings great inconvenience to each maintenance. Because of the poor maintenance environment and the large number of loose bolts, each maintenance time takes more than 4 hours. Now after using this kind of high-strength anti loose bolt, at the beginning, the spot inspectors are also worried about loosening after using it for a period of time, After a period of observation and the operation of the equipment, it has been proved that this kind of bolt does have its unique anti loosening effect, and there has been no loosening since its installation and use. (end)

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