Channels for increasing the service life of rolling mill nuts
Li Huimin, the channel to improve the service life of the nut under the pressure of the milk machine, Libeimin proposed that the lubrication system of the 825 roughing mill of Beiman Special Steel Co., Ltd. was originally open lubrication, and the service life of the pressed nut was short and the oil consumption was large, polluting the environment. The open lubrication system was changed to a closed lubrication system, and the anti-grinding was added to the lubricating oil, and the thrust pad which was in contact with the screw was improved, which overcomes the above disadvantages and achieves good results. .
The rolling mill presses the nut easily, and the short life is a common problem, which seriously affects the normal operation of the rolling mill.
Beiman Special Steel Co., Ltd. 825 rolling mill was put into operation in 1957. After three years of use, it has made great contributions to the revitalization and development of Beigang. However, due to long-term load shedding, the equipment is aging, and there are many existing problems. For example, the original design of the lubrication system is open lubrication. In order to reduce the fuel consumption, the oil supply is controlled as much as possible, so that the pressure is reduced, and the mother is not ideal. . It is only necessary to use 78 months to press the nut to replace the new one. At the same time, the pressing part increases the consumption of lubricating oil, and the waste is serious. In order to change this situation, we changed the open part of the sliding system to the closed lubrication system, and added energy-saving anti-wear agent according to the total amount of fuel to increase the service life of the nut.
1 Lubrication system modification The existing oil supply system supplies the lubricating oil to the pressing nut, and the nut is bare between the thrust pad. To solve the oil return problem, the lubricating oil must be solved by pressing the nut to the end. Splash between the pads, and ensure that the iron oxide cooling water does not splash into the lubricant. We protect the pressure between the nut and the thrust pad and close it. Since the pressing device is moving, we designed the protective cover to be able to expand and contract with the pressing nut. The upper part of the telescopic sleeve is connected to the flange of the pressing nut, and the lower part is connected to the flange of the upper part of the thrust pad, so that the pressing nut and the thrust pad are closed, and the returning oil position is higher than the thrust Open the hole at the block, 2. Ensure that the thrust block is immersed in the lubricant. A sub-tank is placed before the total fuel tank of the returning station, and the return oil is returned to the main tank after the sub-tank is settled. Lubrication of the entire depressed screw shaft becomes a closed lubrication system.
2 Adding energy-saving anti-wear agent to the lubricating oil. Any pair of friction pairs, no matter how high the precision of processing, the surface is actually uneven. When the friction pairs are in contact with each other, the actual contact is only the convex points of the friction and the secondary surfaces. These points only occupy less than a thousand of the macroscopic area of ​​the frictional secondary surface, but carry almost the entire macroscopic pressure. That is to say, the partial pressure at these points is more than a thousand times the macroscopic calculation pressure. Under such pressure, the oil film formed by the originally thin frictional surface peaks will inevitably rupture, causing direct contact between the metals. The raised points of direct contact between the metals constitute a major part of the macroscopic friction. The main cause of metal wear is that there is a direct contact between the raised points of the rubbing surface, so-called dry friction. Therefore, when considering friction and wear, that is, lubrication, first of all, we should consider how to solve the lubrication problem of the convex points between the friction pairs. However, the ordinary lubricating oil is powerless, and the energy-saving anti-wear agent just solves the problem of the instantaneous high temperature and gold generated by the direct contact of the convex side of the frictional surface, the chemical activity caused by the distortion of the lattice, and the molecule of the anti-wear agent. Chemically reacts with the raised points of the MOP to form a pliable compound. This compound re-separates the metal that has been in direct contact, and even if the metal itself has lubricating properties, the frictional resistance is greatly reduced, thereby reducing the macroscopic friction coefficient and the amount of wear. It can be said that the energy-saving anti-wear agent is actually a kind of gold and a surface treatment agent. it's here. Lubricating oil is essentially the carrier of energy-saving anti-wear agent, and the preliminary calculation of the friction pair can save more than 300,000 yuan after the improvement of each roller. The manufacturing cycle of the backup roll is reduced. It is expected that the inlaid support roller will be used on the date of receipt 2, and the life of the overall support roller will be the same as that of the overall support roller at the end of June 29, and sometimes even higher than the former. The author has a cold-rolled sheet of Bengang Group, which has a negative experience in the city of Liaoning Province. month. The service life of the nuts of our factory 825 rolling mill is expected to be extended from the original 8 months to 14 months. 1 The lubrication condition of the 8001 large shear reducer for the herringbone gear frame provided by the oil station has been significantly improved. The application of energy-saving anti-wear agents will also increase the output power of the system, reduce the oil temperature of the lubrication system, and enable the cold-start of the lubricating oil in the case of low ambient temperature.
Received on July 4, 2001, the main lubrication and protection, or energy-saving anti-wear agent molecules. It can be seen that some physical and chemical properties of lubricating oil, such as acidity viscosity, are meaningless. Because even if the water is used as a carrier, the anti-wear agent molecules can exert good anti-wear and anti-wear effects under severe working conditions.
It significantly reduces the effect of the friction coefficient from Harbin Institute of Technology machinery. The energy-saving anti-wear agent friction coefficient curve 3 tested by the engineering department can be seen.
Type, the upper sample material is, 15 bait sink = 60, the next sample material is 2 collection! 05.
From the test curve, it can be seen that when the load is 4. The friction coefficient is reduced by 54.6; when the load is 900, the friction coefficient is reduced by 75; when the load is 1300, the friction coefficient is reduced by 61.8; when the load is 190, the friction coefficient is decreased by 62.5.
Last year, when we were repairing in the company's 825 rolling mill, we added energy-saving anti-wear agent to the fuel tank of the oil station according to the total amount of lubricating oil. Since the friction coefficient of the screw and the nut is greatly reduced, it may cause the pressing mother to run. When it happens back to the pine elephant. To this end, we have improved the thrust pad that is in contact with the screw, and increased the contact area between the screw and the thrust pad to limit the occurrence of looseness.
3 Conclusion According to the effect of some anti-wear agents pressed by the 50 rolling mill of Baotou Iron and Steel Co., Ltd., the pressure of the nut is extended from the original service life to 18, and the transformation of the centrifugal joint of the chestnut is opened. Wu Dilu Shu Xin Ding Tianli will pass the centrifuge. After the pump-claw type elastic coupling is changed to the elastic pin type, the labor string of the worker can be reduced, the inspection time can be saved, and the boring hole of the base can be protected.
In 1996, our factory's ammonium nitrate workshop replaced two ammonium nitrate melt pumps, using the 240402250 corrosion-resistant centrifugal pump produced by Dalian Acid-resistant Pump Factory. After a period of use, we found that the pump maintenance was time-consuming and laborious, and the motor foot on the base lost the bolt hole. We have modified the couplings of the chestnuts and solved the above two difficulties. The pump structure and working conditions. The pump is a rear-opening centrifugal pump. The design is simple and compact. The pump efficiency is good, and the original pump drive power. 45 evaluation new pump 301 xian pump body through the two sides of the foot on the base, and the inlet and outlet pipes are connected, the pump frame with right angle support, the original claw-type elastic coupling 1.
The working environment of the pump is harsh, the working medium is molten ammonium nitrate solution, the specific gravity is 7=148, the temperature is 175 ft, the flow rate is 2228,13, and the new pump appeared in the use of the new 1.2 after the initial installation and use. Insufficient operation and maintenance experience, the pump can not run for a long period of time, so itching is frequent, and due to the structure of the pump, regardless of the mechanical seal of the impeller bushing or the replacement of the bearing, it is necessary to take the pump frame together with the rotor components such as the impeller. The pump body is pulled out, and the motor must be moved at this time. After the repair is completed, the motor is repositioned and re-aligned. In this way, each time the inspection is carried out, the motor is moved back and forth, and the labor intensity of the workers is great. Sometimes the motor slides down the base, and it is still necessary to find a heavy machine to hang up, and it is cumbersome and time-consuming. In addition, the threaded hole of the cast iron base has been frequently disassembled, and there is a tripping phenomenon. The motor is not tight, and there is severe vibration during the operation. The threaded hole has to be reamed and tapped. If there is another trip, Difficult to handle.
2 Coupling transformation 2.1 Reconstruction assumption and selection We have carefully considered and modified the pump coupling section. The modified coupling can be taken out from the pump body for maintenance without removing the pump body and moving the motor. After comparison, we chose the elastic ring pin coupling 2.
2.2 Coupling size determination After the transformation of the coupling, the length of the middle section is greater than the rotor extension of the pump body length of about 85, and the gap 1 is greater than the mouth boss 6, the middle section of the gap size is greater than B3, In order to ensure the smooth removal of the pin. After field measurement, the size of B 2 should be 127mm.
According to the standard of the coupling, the allowable torque of type 83 of é‚›1086 is 46,6kg, m.6 M2 standard pin, the gap value a is 2,6mm,
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