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Rolling mill oil film bearing lubrication of these knowledge you must be clear!


Release time:

2021-09-17

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Oil film bearings belong to the sliding bearing family, in the working conditions, in the full fluid lubrication state. Oil film bearings use the principle of fluid dynamic pressure lubrication, that is, by the relative movement of the shaft and the bearing element, the fluid dynamic pressure formed by the viscosity of the lubricating oil and the wedge gap in the bearing pair is used to form a bearing that carries the oil film.


The bearing oil film is also called the pressure oil film. It balances the load, isolates the journal and the shaft sleeve, converts the solid friction between the metals into the molecular friction inside the liquid, and minimizes the friction and wear, so it can be within the maximum range Meet the requirements of bearing pressure, impact resistance, transformation speed, rolling accuracy, structural size and service life.


Therefore, oil film bearing lubrication, often in the following three forms:

(1) When starting or stopping, although there is lubricating oil between the shaft and the bearing, because the movement speed is equal to zero or approaches zero, the hydrodynamic lubrication has not yet formed or gradually disappeared, and the shaft and the bearing must be in direct contact. Side lubrication is even semi-dry friction.

(2) mill operation, due to vibration or excessive water or insufficient oil supply or oil quality problems may produce mixed lubrication.

(3) When the rolling mill runs normally and smoothly, it is lubricated by fluid.
Therefore, the lubrication of the oil film bearing is characterized by the mixed lubrication of the above three situations.


In order to meet the needs of high speed, heavy load, automation, large-scale and high yield of steel enterprises, to solve the lubrication requirements of rolling mill oil film bearings, to meet the increasingly harsh working conditions, the lubricating oil used in rolling mill oil film bearings-oil film bearing oil came into being.


1. Performance requirements for oil film bearing oil
The lubrication characteristics of the oil film bearing of the rolling mill determine that the oil film bearing oil must meet its performance requirements in order to ensure the normal operation and continuous production of the rolling mill. Oil film bearing oil shall have:
(1) Excellent viscosity-temperature performance (high viscosity index), when the bearing temperature changes greatly, the normal lubrication of each lubrication part can still be realized.
(2) superior anti-emulsification performance (I. e. water), in the long-term use can quickly separate the water in the oil.
(3) Good anti-wear and extreme pressure performance, when a small amount of water is mixed into the oil during operation, the jaw breaker. Can still form an oil film to maintain heavy load and anti-wear performance.
(4) Good anti-wear, anti-rust, anti-foam performance, prevent the lubrication system from rusting, blocking the oil circuit, causing wear and insufficient oil supply.
(5) good oxidation stability, cleaning and filtration. Make the lubrication system oil smooth, ensure the normal lubrication.

2. Lubrication management and use requirements of oil film bearing oil
Data show that more than half of the main causes of mechanical failure or early wear are related to lubrication technology management. Do a good job in lubrication management, prevent bearings, gears and other friction moving parts of the scratch or sintering, prevent and reduce wear, reduce friction resistance, roller crusher. Preventing equipment accidents, improving equipment production efficiency, saving energy, improving energy efficiency and increasing economic efficiency are the main tasks of lubrication management.

1) lubrication management is a professional technical management, should be set up full-time lubrication technical management personnel, formulate lubrication management system, lubrication technical knowledge training.
2) Under the premise of reasonable oil tank capacity, maintain a reasonable oil level in the oil tank, and often add lubricating oil to the oil tank to make the oil in the oil tank always at a reasonable operating oil level, which is beneficial to oil degassing, precipitation, separation of water and reduction of oil temperature in the tank.
3) Timing and positioning extraction of oil samples in operation, from the oil odor, color, viscosity change, water content, water separation performance, pollutant category and content, anti-foam performance for testing and testing. When the water content of the oil entering the lubrication point exceeds 0.1%, the mechanical wear increases sharply; the lubrication condition exceeding 0.5% will be very dangerous. Compare Hubei test crusher. Record the inspection.
4) Analyze and compare the records of each test, predict and forecast the bad lubrication state, and formulate improvement or prevention measures. The oil level, oil quality, oil temperature and oil pressure control alarm and interlock of the system shall be safe and reliable to prevent the occurrence of lubrication accidents.


3. Prevent oil mixing and control oil pollution
(1) There should be a strict management system for the purchase, storage, storage, issuance and waste oil treatment of oil products, which should be carried out according to different varieties and grades, and there should be obvious signs or signs that are easy to distinguish, indicating the name, grade, date, etc. Mixed storage is strictly prohibited to prevent oil mixing accidents caused by misuse.
(2) During storage, transportation and storage, the cleanliness and airtightness of the container shall be strictly ensured to prevent the intrusion of dust, impurities and rainwater. Should be stored in the dark, cool and ventilated warehouse with fire escape. Temporary open storage, should keep the lid slightly inclined position, to prevent rainwater intrusion. Oil products should not be in contact with metals such as copper and lead that promote oxidation reactions.
(3) Main items of lubricating oil acceptance re-inspection: viscosity, viscosity index, water content, emulsification resistance and extreme pressure. Cleanliness requires mechanical impurities within 0.01%, no moisture and sediment traces, etc.
(4) The manhole cover on the top of the fuel tank should be tightly covered and not open. The filter accuracy of the air filter is above 100 mesh, which shall be checked and cleaned regularly, and the drain valve at the lower part of the oil tank shall be discharged regularly. The lubricating oil shall be added to the oil tank and pumped by pipeline, and a filter with appropriate filtration accuracy shall be installed. The oil tank shall be regularly cleaned of precipitated oil sludge, and the inner surface of the oil tank shall not be wiped with fiber fabric.
(5) When replacing the clogged filter element, the oil in the filter cartridge should be drained to prevent dirt from entering the downstream pipeline of the filter, causing serious and irreparable secondary pollution, otherwise it will directly endanger the normal lubrication at the lubrication point.
(6) According to the changes in the color, viscosity, moisture and pollution of the oil in use, change the oil on time according to the quality.


4, the first use of oil film bearing oil
In addition to the original lubrication system and equipment for a comprehensive and thorough cycle cleaning, but also to do the following work:

(1) The standard value and actual test value of the physical and chemical performance index of the oil film bearing oil are compared and analyzed with the physical and chemical indexes of the oil products of relevant manufacturers at home and abroad, and combined with the working conditions of their own equipment, the work plan for alternative use and the technical measures when accidents occur are worked out, so as to be foolproof.
(2) The oil department should organize relevant technical personnel to analyze and discuss the technical data of oil products in order to fully understand the performance of oil products and correct use methods.
(3) In the mixing test of new oil products and in-use oil products, the compatibility or chemical reaction between the two, the objective situation of oil quality changes should be recorded, and the relevant physical and chemical performance data should be tested.