Low temperature bearings are not designed to operate stably in high temperature environments like high temperature bearings. Instead, they are designed with special materials and structures to reduce friction and minimize frictional heating, thus maintaining low temperatures during prolonged operation.
Bearings that operate at temperatures below -60℃ are considered low temperature bearings.
They are primarily used in various liquid pumps, including those for liquefied natural gas, liquid nitrogen (hydrogen, oxygen), butane, rockets and missiles, spacecraft, and more.
Low Temperature Bearing Operating Temperature
Operating temperature is a crucial indicator for global bearing brands.
The operating temperature of a low-temperature bearing reflects the technology and processing level of the bearing material and manufacturing.
Measurements are mainly made based on the temperature difference between the bearing outer ring and the refrigerant oil injected during operation.
Lower operating temperatures result in longer bearing life and better performance.
World-renowned bearing manufacturers, leveraging their respective strengths, aim to gain a competitive advantage in low-temperature bearings across various industries.
For example, Timken's spherical roller bearing has undergone rigorous testing, resulting in an operating temperature that is about 15.5 degrees Celsius lower than similar products on the market, while other well-known international brands have operating temperatures exceeding 19 degrees Celsius. .
Low Temperature Bearing Product Category
Low temperature bearings are typically single row deep groove ball bearings and cylindrical roller bearings.
The phenomenon of sticking in low-temperature bearings is caused by external factors such as temperature changes and internal factors such as the difference in thermal expansion coefficients between the shaft, structure and materials.
When the temperature range is significant, the contraction of different materials is uneven, leading to tighter clearance and binding.
Therefore, for equipment that operates over a wide range of temperatures, including low-temperature equipment, it is important to calculate the expansion coefficients of materials and use materials with similar coefficients for optimal performance.
In terms of structural design, it is best to avoid using tapered roller bearings at both ends of the shaft. This configuration can result in binding as the distance between the two bearings increases.
If a pair of tapered bearings are installed at one end of the shaft for positioning, the axial movement of the shaft will be restricted, while the other end of the shaft can be equipped with a bearing, which limits only the radial force and can move axially within a certain range due to axial temperature changes.
Low temperature bearing material selection
Steel selection for low temperature bearings
Low temperature bearings are typically made of stainless steel such as 9Cr18 and 9Cr18Mo, or materials such as beryllium bronze, ceramic and others.
For extremely low temperatures (limit temperature -253 ℃), 6Cr14Mo material can be selected, but it should only be used in a vacuum environment.
Note: When using low temperature bearings, it is important to be aware of lubrication-related burns, so choose an appropriate lubricant accordingly.
Bearing Material List and Operating Temperature
steel system |
Materials science |
Work temperature |
Comments |
High Temperature Bearing Steel |
GCr4Mo4V |
≤315℃ |
|
GCr14Mo4 |
≤330°℃ |
Corrosion resistant medium |
|
High speed steel |
W6Mo5Cr4V2 |
≤430℃ |
|
W9Cr4V2Mo |
≤450°℃ |
||
W18Cr4V |
≤550°℃ |
||
High temperature carbureted bearing steel |
H10Cr4Mo4N |
≤550°C |
For large carbureted bearings |
i4VRR6027 |
|||
Heat resistant stainless steel |
4Ch13 |
≤400℃ |
Corrosion resistance at high temperatures |
3Ch13 |
≤400℃ |
Corrosion resistance at high temperatures |
|
2Ch13 |
≤600℃ |
Nitriding treatment is required. High temperature and corrosion resistance |
|
1Ch13 |
≤650℃ |
Nitriding treatment is required. High temperature and corrosion resistance |