Smooth characteristics of steel metallurgical machinery (2)
2024-01-17 08:08:31
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Smooth characteristics of steel metallurgical machinery (2)
Source: China Bearing Network Time: 2018-02-04
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Oil film bearing is the principle of dynamic pressure smoothing using fluid; that is, the relative movement of the shaft and the bearing element; the fluid dynamic pressure formed by the viscosity of the smooth oil and the wedge-shaped gap of the oil in the bearing pair; and the bearing that carries the oil film .
The bearing oil film is also called pressure oil film; it acts to balance the load, block the journal and the bushing; convert the solid collision between the metals into the molecular conflict inside the liquid; reduce the conflict wear to the minimum limit; thus it can be in the maximum range Satisfied with the requirements of bearing pressure, impact resistance, changing speed, rolling precision, layout scale and service life.
According to the Reynolds equation; the rolling pressure, rolling speed, bearing clearance and smooth oil viscosity are matched; the uninterrupted and stable bearing oil film is formed; the liquid dynamic pressure is smooth; the conflict of the rolling mill under different working conditions is satisfied. Smooth with smooth, that is, in the start, stop, forward rotation, and rotary change, in a semi-dry conflict and edge conflict; smooth in the collision of impact load or a lot of incoming water; in normal operation and full load; Liquid conflicts with smoothness.
Therefore, the oil film bearing is smooth; often reflected in the following three methods:
(1) Starting or stopping; although there is smooth oil between the shaft and the bearing; but because the moving speed is equal to zero or close to zero; the fluid dynamic pressure is not formed smoothly or gradually disappeared; the shaft and the bearing must be touched straight; Smooth and even semi-dry conflict situations.
(2) In the operation of the rolling mill; because of the sensation of sensation or excessive water supply or lack of oil supply or oil quality problems, it can be mixed and smooth.
(3) When the rolling mill operation is normal and stable; the fluid is smooth.
Therefore, the smooth characteristics of the oil film bearing is the smooth mixing of the above three conditions.
In order to meet the needs of high-speed, heavy-duty, active, large-scale and high-yield steel enterprises; to deal with the smooth demand of rolling mill oil film bearings; to meet the increasingly demanding working conditions; the smooth oil used in rolling mill oil film bearings - oil film bearing oil should be transported Health.
Fourth, the application of oil film bearing oil requires the smooth characteristics of the oil film bearing of the rolling mill; it is determined that the oil film bearing oil needs to be satisfied with its functional requirements; the normal operation and continuous production of the rolling mill can be guaranteed; therefore; the oil film bearing oil needs to have:
(1) Excellent viscosity-temperature function (high viscosity index); when the bearing temperature is greatly changed; the smoothness of each smooth part can still be completed.
(2) The superior anti-emulsification function (ie water-separation); in the long-term application, it can be agile away from the oil.
(3) Outstanding anti-wear and extreme pressure function; when the oil is mixed with a small amount of water during operation; still can constitute the oil film to adhere to heavy load and anti-wear function.
(4) Outstanding anti-wear, anti-rust and anti-foam functions; avoid rusting of smooth system; block oil passage, constitute wear and lack of oil supply.
(5) Outstanding oxidation stability, scavenging and filtering properties. Smoothing the smooth system oil circuit; ensuring smooth and normal.
V. Smooth handling and application requirements of oil film bearing oil
(1) The smooth processing materials of oil film bearing oil are marked; the primary cause of mechanical failure or early wear; more than half are related to smooth skill handling. Do a good job of smooth handling; avoid scratching or sintering of conflicting moving parts such as bearings and gears. Avoid and reduce wear and tear; reduce conflict resistance; avoid equipment attacks; improve equipment production power, save power; improve power useful rate; add economic benefits; is the primary task of smooth handling.
1. Smooth handling is a professional skill management; full-time smooth skills should be set up for personnel; smooth management system should be formulated; smooth skill knowledge training should be carried out.
2. Under the premise of reasonable fuel tank capacity; adhere to the reasonable oil level of the fuel tank; often add smooth oil to the fuel tank; keep the oil in the fuel tank at a reasonable operating oil level; degas the oil; deposit the machine; The oil temperature in the box is favorable.
3. Punctuality, positioning and extraction of oil samples during operation; testing and testing of oil odor, color, viscosity change, water content, water separation function, pollutant type and content, anti-foam function, etc. At 0. 1%; the mechanical wear is sharply added, and the smooth condition beyond 0. 5% will be very risky.
4. Analyze the record of each test; make a prediction for the unsatisfactory smooth condition; formulate an improvement or prevention method. It is safe and reliable for the oil level, oil quality, oil temperature, oil pressure control alarm and interlocking of the system; The episode.
5. Avoid contamination with oil and handling oil:
(1) Oil product procurement, storage, storage, distribution and disposal of waste oil; there should be a strict handling system; according to different types; trademarks should be separated; there are significant easy to distinguish signs or marks; mark the name; trademark; Date, etc. Prohibit mixed storage; avoid misuse to form a mixed oil incident.
(2) During storage and storage; it is necessary to strictly ensure the sanitation and sealing of the container; to avoid the intrusion of dust, impurities and rain. It should be protected from light; cool and ventilated; warehouses with fire exits. Temporary open storage; The lid of the bucket adheres to the orientation of the skewed state; in order to prevent the intrusion of rainwater, the oil does not touch the metal with the copper oxide and lead to promote the oxidation reaction.
(3) The first item of smooth oil inspection and re-inspection: viscosity, viscosity index, water content, demulsibility, extreme pressure. The mechanical impurities in the hygiene requirement are within 0.01%; no moisture and sediment marks.
(4) The manhole cover on the top of the fuel tank should be tightly closed; do not open. The air filter has an accuracy of 100 mesh or more; watch the sorting on time; the drain valve in the lower part of the fuel tank is punctually discharged. Add smooth to the fuel tank. The oil is pumped by pipeline; and the filter with proper filtration precision is installed. The fuel tank should be defensively arranged to deposit sludge; it is not allowed to wipe the fuel tank table with fiber fabric.
(5) When replacing the blocked filter element; the oil in the filter cartridge should be drained; beware of dirt entering the filter downflow pipe; constitute a severe irreparable secondary pollution; otherwise it will directly endanger the smoothness at the smooth point.
(6) Change the status according to the target of color, viscosity, moisture and pollution degree of the oil used; change the oil on time.
6. The unit that uses oil film bearing oil for the first time; in addition to the complete circulatory removal of the original smooth system and equipment; the following operations must be done:
(1) The standard value and practical test value of the physical and chemical function target of the oil film bearing oil; compare with the physical and chemical goals of the manufacturer's oil products in the national watch; contact the condition of the equipment condition; develop the operation plan and accident instead of the application Skills at the time of the situation; be confident.
(2) Some oils should be arranged for the skilled personnel to analyze and discuss the oil skill data; in order to fully understand the function of the oil and the correct application method.
(3) Mixed experiment of new oil and oil in use; compatibility or chemical reaction between the two; the objective condition of oil quality change should be recorded; and the related physical and chemical function data should be tested.
(B), the application of oil film bearing oil in the equipment:
1. Skills requirements for smooth system equipment:
Smooth equipment is necessary to fully control the oil quality, oil temperature, oil pressure and oil level; reduce the intrusion of pollutants on the online smooth oil. The following skills are required for the equipment:
(1) Two tank equipments; one for one; punctual switching; spare tank removal; oil temperature deposition; net oil water.
(2) The volume of the fuel tank should be 35 to 40 times of the displacement per minute of the oil pump; some or even larger. Under the condition of high oil level operation; ensure that the oil meets the long deposition time in the fuel tank.
(3) The oil tank should be equipped with a degassing plate in the oil return zone - reduce the impact of the fuel oil flow, the magnetic grid equipment - the iron machine in the oil returning area, the floating suction port - the proper orientation under the liquid surface, the active drainage device or the flooding alarm Equipment - will discharge the separated water in time, dynamic liquid level control - alarm or interlocking for a lot of oil leakage.
(4) The oil supply filtration precision is high; usually the filtration precision reaches 10~20μm to ensure the hygiene of the oil.
(5) The oil supply temperature should be controlled between 40±2°C; ensure the viscosity of the oil supply.
(6) It is necessary for the filter to drain the remaining air in the filter cartridge before switching.
(7) The oil supply pressure should be kept stable; the smooth system operation pressure control equipment should have high sensitivity and precision; avoid the change of pressure; the pressure drop of the attack operation; the lack of oil supply of some smooth system; the wear and sintering of the oil film bearing .
(8) The pressure tank in the smooth system needs to operate normally; control the reasonable oil filling flow value and the liquid level in the tank; play some buffer system pressure shaking and emergency oil source supply.
(9) After the smooth equipment starts to supply oil, there should be a certain timing of the oil supply cycle; the temperature of the smooth oil supply pipeline and the smooth part of the equipment will reach or approach the oil supply temperature; it is beneficial to the composition of the oil film at each smooth point. It is also beneficial to drain the remaining gas in the oil supply pipeline.
(10) The heating temperature of the oil in the fuel tank should not be too fast; together with the best pump to carry out the oil circulation; to avoid some oils that are overheated and mutated. When heating and sedimenting, the oil heating temperature should not exceed 65 °C. .
(11) The timing of rolling mill start-stop acceleration and deceleration is better; reducing mechanical oscillation impact and affecting oil film strength.
2. Removal and commissioning of smooth equipment:
The cleaning of the smooth equipment is divided into two conditions: the new system and the online operation system; usually the system pipeline is used; the flushing method is used for the flushing. About the new smooth system; refer to the standard of the Ministry of Metallurgy Department YBJ207-85 metallurgical machinery equipment construction and inspection standard hydraulic The implementation of the relevant skill rules for pneumatics and smooth systems. The key aspects of the cyclical scouring of the online application system are as follows:
(1) Discharge the original oil in the smooth system and equipment.
(2) Clear the fuel tank; check the inner wall of the tank; the paint layer or rust inhibitor coating should be intact; there is no appearance such as rust and falling; there should be no visible pollutants.
(3) The circulation flushing circuit should separate the smooth point of the equipment from the flushing circuit; there is no dead angle pipe section; and the shut-off valve in the circuit; the throttle valve and the pressure reducing valve are adjusted to the maximum opening degree.
(4) Purify the oil with pure low-viscosity base oil; compatible with the system working medium. The flushing oil should be filtered to participate in the fuel tank; the filtration accuracy should not be lower than the filtration precision of the system. The flushing oil temperature does not exceed 60 °C. .
(5) The flushing oil should be fully touched with the inner wall of the flushing circuit; the flushing flow rate should make the oil flow turbulent; the oscillating pipeline should be used in the flushing process to enhance the flushing effect.
(6) Excavate the scouring oil sample from the outlet pipe of the filter to the end of the oil supply main pipe for inspection. Continue to carry out 2-3 times; the average value reaches the hygiene level. The oil sample is taken strictly according to the rules. Sampling containers need to be hygienic; avoid oil distortion.
(7) After the system has passed the scouring; the scouring oil is completely cleaned; the residual liquid is not left. To avoid the viscosity of the working oil, it is necessary to use the working oil for scouring; and check accordingly; ensure the smooth system is put into operation Hygienic degree.
(8) After the working oil is filtered to participate in the fuel tank to the high oil level; carry out the control of the oil temperature, oil pressure, oil level and oil quality of the system; and check the operation alarm and interlock of the smooth system; Working.
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