In recent years, the existing ordinary wire rod mills in the country have undergone different degrees of technological transformation. After the transformation, the weight of the main and auxiliary equipment has increased greatly. , which puts forward higher requirements for equipment lubrication.
The general wire rod workshop of Handan Iron and Steel Co., Ltd. has made a bold attempt at equipment lubrication. At the end of 1997, the workshop carried out the first-fired and speed-up transformation and added three Ø530 rolling mills, two Ø450 rolling mills, two Ø400 rolling mills, and start-stop flying shears. One, and the gears of the reducer are all changed to hard tooth surfaces or semi-hard tooth surfaces. The original thin oil lubrication system cannot meet the needs of the equipment in terms of capacity and performance. The old thin oil lubrication system needs to be completely remodelled. The core of the improvement is to improve oil quality, ensure oil pressure and oil quantity, ensure oil supply temperature, and at the same time ensure that the improved equipment is easy to maintain, economical and practical.
1. According to the location of the equipment, reasonably arrange the gas station
Firstly, the main equipment is divided into three areas, namely: rough rolling area, middle rolling area and finishing rolling area. The centralized layout of equipment partitions is conducive to the establishment of a centralized lubrication system. Centralized lubrication has its obvious characteristics:
(1) The pressure oil supply has sufficient supply volume, which can ensure the lubrication of a large number of lubricating points with wide distribution, and take away the heat generated by the friction pair at the same time.
(2) Mechanical impurities such as metal abrasive particles on the friction surface can be taken away with the oil and washed away to achieve good lubrication, reduce friction, reduce wear, reduce consumption of wearing parts, reduce power consumption, and prolong the service life of the equipment.
Set up a 1# lubrication station near the rough rolling area, mainly for the lubrication of the fifth continuous rolling reducer, K17~18 reducer, herringbone gear seat and flying shear in the rough rolling area;
Set up a 2# lubrication station in the original thin oil station, which is equipped with three sets of lubrication systems, which are respectively used for the lubrication of the intermediate rolling area, the finishing rolling area and the 8M main motor;
Considering that the 7M main motor and the 9M main motor are located far away, and the respective consumption is very small, a small thin oil station is separately set up near the two motors, and placed underground without occupying the ground. They are respectively 3# and 4# lubrication stations, In this way, a complete set of centralized lubrication systems for main engine equipment is formed to ensure sufficient and reasonable lubrication of each equipment.
2. Combined with equipment operation status, improve oil supply quality
At present, in order to further meet the lubrication needs of each rolling mill equipment, economical use and advanced unity are achieved in the selection of lubrication equipment and oil products.
1) Selection of oil products
In order to complete the transmission of motion and power, the selected gear oil should play the best role in the following aspects:
(1) Prevent and reduce friction and wear between tooth surfaces, distribute load evenly,
(2) Fully take away the heat generated during friction.
(3) Insulate the tooth surface from water and air to avoid rust, corrosion and dust attack.
(4) Wash the particles and impurities on the tooth surface.
(5) Slow down the gear vibration and make the movement smooth.
(6) It has a good lubricating effect on the bearing and good fluidity.
According to the above requirements, the workshop combines the characteristics that the rough, medium and finish rolling reducers mostly work in the environment of high temperature, high load, water and dust. For the convenience of oil exchange and backup, N220# heavy-duty extreme pressure gear oil is selected. It is much better than mechanical oil in terms of extreme pressure, anti-wear, anti-corrosion, anti-foam and anti-emulsification.
|Rough and middle rolling area||Finishing rolling area||Main motor|
|Tank volume m3||25||16||0.63|
|Oil||N220# heavy-duty extreme pressure gear oil||N220# heavy-duty extreme pressure gear oil||30# mechanical oil|
2) Improvement of oil return filter
Old-style thin oil lubrication stations generally have a magnetic filter installed between the oil return pipe and the oil tank. Due to the unreasonable structure of the magnetic filter, the high viscosity of the oil, and the action of the magnetic field, cleaning is very difficult. Due to untimely cleaning, the magnetic substances in the oil often increase, the oxidation is accelerated, and the performance of the oil is reduced.
The new type of magnetic grid filter is a magnetic bar composed of small permanent magnets with strong adsorption force placed at intervals in the stainless steel cylinder, and the small round magnets are separated by non-magnetic substances. A plurality of magnetic rods are evenly arranged vertically and horizontally and placed vertically to form a magnetic grid. When the oil passes through the stainless steel cylinder, it is in full contact with the magnetic rod, and tiny mechanical impurities are adsorbed on the surface of the magnetic rod. One hand can easily take out the magnetic rod from the top of the oil tank, and the other hand can hold the magnetic rod with silk cloth. Wipe off the absorbent, just once a week. The size of the magnetic grid device varies with the flow rate, with more magnetic rods, the cleaning cycle is relatively longer. The magnetic field strength of the magnetic bar should also be at a certain value, and the density of the magnetic grid arrangement is related to the magnetic field strength.
For new oil depots or oil depots with relatively large space, the magnetic grid device can be installed on the oil return pipe outside the fuel tank, and the original magnetic filter only needs to pull out the magnetic core. For old oil depots or oil depots with relatively small space, the magnetic filter between the original return oil and the oil tank can be cancelled, and the magnetic grid device can be placed at the position of the original magnetic filter. Make the tiny magnetic particles in the oil be adsorbed on the surface of the magnetic rod, and prolong the process of oil precipitation in the oil tank. The use of the wire rod workshop of Handan Iron and Steel Co., Ltd. proved that the mechanical impurities were above 0.30% before the transformation, and the impurity content after the transformation was 0.02%~0.03%, which achieved obvious results and greatly reduced the labour intensity of workers.
3. Correctly select the oil pump to ensure oil supply oil pressure and oil quantity
The supply of lubricating oil should not only ensure the oil quality but also ensure the oil pressure and oil quantity. Old-style lubrication stations mostly use two gear pumps, one for standby and one for use. The oil supply of the gear pump has defects such as pulsation, serious oil traps, large leakage, large vibration, short life, high noise, and low pressure.
The following measures can be taken to solve the above problems:
1) Oil pump modification
In order to eliminate the oil supply defect of the gear pump, a screw pump can be used. The screw pump has no dead volume, the oil conveyed moves in a straight line at a uniform speed, there is no phenomenon of oil shortage, stable flow pressure, stable and reliable operation, low noise, tight and durable seal, and the life of the screw pump is 4 times that of the gear pump. Very useful in high cases.
2) Add a pressure setting valve.
A constant pressure valve is added to the main oil supply pipe behind the oil pump. The instantaneous fluctuation of the oil supply pressure can stabilize the oil pressure by directly controlling the opening of the constant pressure valve to ensure the relative stability of the oil pressure.
4. Take effective measures to control the oil supply temperature
The oil temperature control of the oil supply system is mainly to heat and cool down the oil so that the oil supply temperature is always within the required range.
1) Lubricating oil heating
The heating method of the old lubrication system mainly adopts steam heating, and the steam heats the oil through the heating pipe at the bottom of the oil tank. This approach has several drawbacks
a. The heating efficiency is low, the heating speed is slow, and it is affected by the steam pressure.
b. The heating pipe is easy to vibrate, which is mainly caused by unstable steam pressure and water content, and the noise is very loud.
c. The heating pipe is easy to leak, and it is not suitable to find it, causing water to enter the oil and emulsification of the oil. Using electric heating can avoid the above defects, and also reduce the damage of steam to the instruments in the station.
2) Lubricating oil cooling
The temperature control of the lubricating oil is mainly to cool down the oil because the lubricating oil lubricates the equipment and also brings the heat generated in the friction pair back to the oil tank, causing the oil temperature to rise. If the temperature rise cannot be effectively controlled, it will not only cause the temperature of the equipment to rise but also accelerate the oxidation of the oil and shorten the service life.
The cooling method of the old lubricating system mainly adopts the tube cooler. Its main disadvantages are a poor heat transfer effect;
The plate heat exchanger is assembled according to a certain number of plates. The thickness of the plates is generally 0.6mm. A mesh channel is formed between two adjacent plates. The cold and hot media flow into their respective channels due to the action of the sealing gasket to form an interval flow. , can be countercurrent or downstream, so that the hot and cold medium can exchange heat through the plate wall. Its main features are high operational flexibility, small heat loss, convenient installation, disassembly and cleaning, and long service life. It is a substitute product for tube coolers. Before the transformation, the oil temperature in summer can be as high as 70°C, and after the transformation, the oil temperature can be controlled below 50°C, which meets the needs of oil products.
5. Control the oil pressure and oil volume of each oil supply point to ensure sufficient and reasonable oil supply
In order to ensure a reasonable oil supply for each lubricating point, pressure gauges, oil flow indicators, and oil flow controllers are added to the pressure pipeline entering the main engine. According to the oil demand of the lubricating point, the oil supply is reasonable to prevent a certain point from lacking oil. And cause damage to the whole machine.
Through a series of modifications to the lubrication system, the needs of the production equipment are basically met, the operating conditions of the equipment have been significantly improved, equipment accidents have been reduced, the service life of the main reducer has been doubled, and the service life of the oil has also been reduced from the original one year. If it is increased to two years, it can save 300,000 yuan per year. This transformation provides a successful experience for the transformation of the lubrication system of the existing ordinary rolling mill. But today, with the rapid development of science and technology, new technologies and new processes are constantly emerging. Only by adopting advanced technology and management methods and further improving and developing existing equipment can we better adapt to production needs and promote further development of production.