Introduction to the method of solving the heating fault of SKF bearing by lubrication

There are several ways to lubricate imported bearings, and each type of bearing and all types of bearings are also different when using lubrication, which is more conducive to maximizing the service life of SKF bearings, which is the highest performance of mechanical equipment. Performance status

1. Oil lubrication:

Viscosity is an important characteristic of lubricating oil. The viscosity directly affects the fluidity of lubricating oil and the thickness of oil film formed between friction surfaces. The viscosity of lubricating oil at SKF bearing working temperature is generally 12-15cst. The higher the speed, the lower the viscosity, and the heavier the load, the higher the viscosity. Commonly used lubricating oils include mechanical oil, high-speed mechanical oil, turbine oil, compressor oil, transformer oil, cylinder oil, and the like.

Oil lubrication methods include:

a. oil bath lubrication

Oil bath lubrication is the most common lubrication method. It is suitable for the lubrication of low and medium speed bearings. Part of the bearing is immersed in the groove. The lubricating oil is brought up by the rotating bearing parts and then flows back to the oil groove. The oil level should be slightly lower than the minimum. The center of the rolling element.

b. drip lubrication

Drip lubrication is suitable for bearing parts that need to supply lubricating oil quantitatively. The amount of dripping is generally one drop per 3-8 seconds. Excessive oil quantity will cause the bearing temperature to increase.

c. Circulating oil lubrication

The filtered oil is delivered to the bearing components by an oil pump, filtered through the lubricating oil after the bearings, and then cooled and used. Since the circulating oil can take a certain amount of heat to cool the bearing, this method is suitable for bearing parts with higher rotational speed.

d. Spray lubrication

The dry compressed air is mixed with the lubricating oil through a sprayer to form an oil mist. In the jet bearing, the air flow can effectively cool the bearing and prevent the intrusion of impurities. This method is suitable for the lubrication of high speed, high temperature bearing components.

e. Injection lubrication

The high-pressure oil is injected into the bearing through the nozzle by the oil pump, and the oil injected into the bearing flows into the oil groove through the other end of the bearing. When the bearing rotates at high speed, the rolling elements and the cage also form a gas flow at the relatively high rotation speed of the surrounding air. It is difficult to send the lubricating oil to the bearing by the general lubrication method. At this time, the lubricating oil must be sprayed by the high-pressure injection method. In the bearing, the position of the nozzle should be placed between the inner ring and the center of the cage.

The bearing is a fixed part of the machine and is the main body of the machine. Its function is basically to maintain the center position of the shaft and the mechanism for controlling the movement. SKF bearings play an important role in any machine. If there is no bearing, the machine will not work.

Many users have reported that when using imported bearings, the fault of the bearing heat is the most common, which will affect the life and performance of SKF bearings. So how is this failure formed? Below, is the knowledge that is summarized for everyone.

1. The oil level is too low and the lubricant is lost from the oil seal;

2. The grease in the bearing housing is completely filled or the oil level is too high. This can lead to excessive lubrication, high temperature or oil leakage;

3. The contact type (friction) oil seal is too dry or the spring is too tight;

4. The inner hole of the bearing box is not round; the bearing box is twisted and deformed; the supporting surface is not flat; the inner diameter of the box hole is too small;

5. The contact type (friction) oil seal is too dry or the spring is too tight.https://www.supplyforever.com/

New process for quenching metal materials

       In the long-term production practice and scientific experiments, people's understanding of the internal state of metal structure changes, especially since the 1960s, the application of transmission electron microscopy and electron diffraction technology, the continuous improvement of various testing techniques, in the study of horses The morphology, substructure and its relationship with mechanical properties, the conditions of martensite with different morphology and substructure, the influence of the morphology, size, number and distribution of the second phase on mechanical properties have been greatly improved. The progress, new quenching processes based on these foundations are also emerging.

       1. Cycle rapid heating and quenching
       The strength of quenched and tempered steel is related to the austenite grain size. The finer the grain and the higher the strength, so how to obtain ultrafine grain with higher than 10 grain size is one of the important ways to improve the strength of steel. . The steel undergoes recrystallization by α→γ→α multiple phase transformation to refine the grains; increasing the heating rate and increasing the crystal center can also refine the grains. Cyclic rapid heating quenching is a new process for obtaining ultra-fine grains according to this principle to achieve strengthening. For example, 45 steel, repeated heating and quenching in a lead bath at 815 ° C for 4-5 times, can make austenite grains from 6 to 12 to 15; and as 20CrNi9Mo steel, with 3000 Hz 200 kW medium frequency induction The heating device is heated to 760 ° C at a rate of 11 ° C / s, then water quenched, increasing the σs from 960 MN / m 2 to 1215 MN / m 2 , the gas from 1107 MN / m 2 , increased to 1274 MN / m 2 , and the elongation remains unchanged , It is 18%.

       2. High temperature quenching
       Here, the high temperature is relative to the normal quenching heating temperature. If the low carbon steel and the medium carbon steel use a higher quenching temperature, the lath martensite can be obtained, or the number of lath martensite can be increased, thereby obtaining a good Comprehensive performance.
       Experiments from the relationship between the carbon content of austenite and the morphology of martensite prove that the steel obtained by quenching the carbon content of less than 0.3% is all lath martensite. However, ordinary low carbon steel has extremely poor hardenability. To obtain martensite, in addition to alloying to improve the stability of supercooled austenite, only the austenitizing temperature and the quenching cooling can be improved. For example, a five-plow plow arm made of 16Mn steel is quenched in a 10% NaOH aqueous solution at 940 ° C and low tempered, and good results are obtained.
       The medium carbon steel is quenched by high temperature to make the austenite composition uniform: more stripe martensite is obtained to improve its comprehensive performance. For example, AISl4340 steel, after quenching at 870 °C, tempered at 200 °C, its σs is 1621 MN / m2, the fracture toughness Kc is 67.6MN / m, and heated at 1200 ° C, pre-cooled to 870 ° C after quenching, 200 ° C tempered, Σs was 1586 MN/m 2 and the fracture toughness Kc was 81.8 MN/m. If compared in the quenched state, the fracture toughness of high temperature quenching is almost double that of ordinary quenching. Metallographic analysis showed that high temperature quenching avoided the appearance of flaky martensite (twisted martensite) and all obtained lath martensite. In addition, a layer of 100-200-pound retained austenite is placed on the outside of the martensite lath, which can buffer the stress concentration at the crack tip and thus improve the fracture toughness.

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