china wholesale slewing gear factory
Table of Contents
1.Are bearing inner rings interchangeable? Can old and new slewing gear be mixed?
Are bearing inner rings interchangeable? When replacing old slewing gears, some manufacturers find that the reasons for the damage and failure of bearing accessories are different, and they want to know if the inner ring of the bearing is damaged, can the inner ring accessories of another bearing be replaced for combined use, and want to extend the bearing life in this way.
The frequency of use reduces the cost of replacing the bearing, but it is also worried that it will affect the service life of the bearing.
1. Can the inner ring of the slewing gear be interchanged?
The inner ring of the slewing gear is interchangeable. In fact, as long as it is the same type of slewing gear or the bearing inner ring with the same bearing suffix, it can be exchanged. In this case, do not replace the bearing’s outer ring type suffix.
The two types of slewing gears are different, so they cannot be replaced. If If it is found that the inner ring of the same model is mixed, it will not affect the quality and life of the bearing after assembly.
Some bearings fail due to various reasons, and some parts of the bearing are in good condition. At this time, it is possible to remove the outer ring of the bearing for use. However, some slewing gears themselves have bearings without an outer ring, and the inner ring of the bearing cannot be taken out independently. ,
At this time, it is recommended that customers do not blindly remove the outer ring to use, so as to waste the cost of an outer ring and increase itself. Replacement should be tried according to the specific conditions of the bearing.
2. Can old and new slewing gear be mixed?
For worrying about whether the operation of using old slewing gear parts to assemble new bearing parts will affect the service life or performance of the bearing, in fact, this also needs to be analyzed in detail. If there are no problems such as wear and deformation of the parts, the new and old bearing parts are suitable for use.
In the case of matching, it can be mixed. However, if the clearances of some accessories are different or do not fit, it is not recommended to mix them, and there may be poor operation or other wear and noise conditions that affect the normal operation of the slewing gear.
However, if the spare parts are of the same type, and there is no wear deformation or other faults after inspection, then the old and new bearings can be mixed.
2.What are the factors that affect the fatigue life of bearing steel?
Factors Affecting Fatigue Life of Bearing Steel
1. The effect of nitrides on fatigue life
Some scholars have pointed out that when nitrogen is added to the steel, the volume fraction of nitrides decreases. This is due to the reduction in the average size of the inclusions in the steel. Limited by technology, there are still a considerable number of inclusion particles smaller than 0.2 in. counted.
It is precisely the existence of these tiny nitride particles that has a direct impact on the fatigue life of slewing gear steel. Ti is one of the elements that form nitrides. It has a small specific gravity and is easy to float. There will also be a part of Ti left in the steel to form multi-angular inclusions.
Such inclusions are likely to cause local stress concentration and fatigue cracks, so it is necessary to control the occurrence of such inclusions.
2. The effect of oxides on fatigue life
The oxygen content in the steel is an important factor affecting the material. The lower the oxygen content, the higher the purity and the longer the corresponding rated life. There is a close relationship between the oxygen content in steel and oxides.
During the solidification process of molten steel, the dissolved oxygen of aluminum, calcium, silicon and other elements forms oxides. The oxide inclusion content is a function of oxygen.
As the oxygen content decreases, the oxide inclusions will decrease; the nitrogen content is the same as the oxygen content, and also has a functional relationship with the nitride, but because the oxide is more dispersed in the steel, it plays the same role as the carbide. , so it has no destructive effect on the fatigue life of steel.
Due to the existence of oxides, steel destroys the continuity of the metal matrix, and because the expansion coefficient of oxides is smaller than the expansion coefficient of the bearing steel matrix, when subjected to alternating stress, it is easy to generate stress concentration and become the origin of metal fatigue.
Most of the stress concentration occurs between oxides, point inclusions and the matrix. When the stress reaches a large enough value, cracks will occur, which will rapidly expand and destroy. The lower the plasticity of the inclusions and the sharper the shape, the greater the stress concentration.
3. The effect of sulfide on fatigue life
Almost all of the sulfur content in steel exists in the form of sulfides. When the sulfur content in the steel increases, the sulfide in the steel increases accordingly, but because the sulfide can be well surrounded by the oxide, the influence of the oxide on the fatigue life is reduced, so the number of inclusions has no effect on the fatigue life.
Certainly, it is related to the nature, size and distribution of inclusions. The more inclusions, the lower the fatigue life must be, and other influencing factors must be considered comprehensively. In bearing steel, sulfides are dispersed and distributed in a fine shape, and are mixed with oxide inclusions, which are difficult to identify even by metallographic methods.
Experiments have confirmed that, on the basis of the original process, increasing the amount of Al has a positive effect on reducing oxides and sulfides. This is because Ca has a fairly strong desulfurization ability. Inclusions have little effect on the strength, but are more harmful to the toughness of the steel, and the degree of damage depends on the strength of the steel.
