Materials to be used for bearing components and rolling elements
Materials that should be used for manufacturing bearing components and rolling elements determine performance of needle rollers and reliability to larger extent. The important factors to consider when deciding upon materials for bearing rollers are hardness, load distributions, fatigue resistance, dimensional accuracy, lubrication conditions etc. After this, it is also necessary to discuss on sealing and caging materials for needle roller bearings. Sealing and caging are two important factors to consider optimizing overall performance of the product.
The most common material that is used by leading industries is steel prepared by combining carbon and chromium together in desired ration. It can also be used to prepare bearing washers and rolling elements. The outer ring of needle rollers bearing is prepared by using thin steel that is always been an exception. For outer rings, mild steel is used most of the times having reliability and suitability for the applications.
Hard steel enables bearing rollers to withstand heavy shocks and it is optimum to work even under extreme operating conditions. Manganese or nickel can also be added to prepare steel as per required strength and application usage. The applications that are operated generally at high temperature like 140 degree Celsius or above, here it is necessary to focus on heat stabilization and dissipation factors.
Cages are generally attached with needle rollers to make it more suitable for any particular application. IT is also responsible to reduce noise levels, bearing shocks, for even load distribution and to improve overall rolling conditions of the bearings. The specifications of cages may vary based on size of bearing either it is small or big.
- Polyamide 66
The most common materials for cages are polyamide 66 and steel cages. The material has excellent sliding properties that can work on different temperatures and operating conditions as per project needs and requirements. The best part about polyamide 66 is that it does not come in contact with lubricant that increases overall life of bearing rollers.
You should use these cages below -40 degree temperature otherwise it may result into cage failures. So this would not be saying wrong that operating temperature and cage aging has strong relationship with each other. The other important features of polyamide cages are low friction, low heat dissipation, and low wear – tear.
- Steel Cages
These cages can be used for the applications that are operated at high temperature up to 400 degree Celsius. They remain unaffected by any type of lubricant or organic solvent even in extreme operating conditions. They are usually window type cages and it can be quickly bended to different shapes and sizes.
In steel cages, carbon content is low and strength is also normal. They are quite light in weight and help in reducing overall frictional movement and optimize speed as well. When operated at normal temperature, steel cages result into low wear and tear plus controls friction as well. Steel cages have wonderful sliding properties that increase overall bearing life and its speeds.
Seal is attached with bearings to increase performance and reliability of needle rollers. The main objective of attaching sealing with bearing rollers is to protect lubricants and organic solvents from solid contaminants.
- Acrylonitrile-butadiene rubber (NBR)
Acrylonitrile-butadiene rubber (NBR) is universal seal material for needle rollers that shows good resistance against minerals, grease, chemicals, petrol, diesel, heating oil, vegetable oil, and fats. At high temperature, material will get harder.
This is an organic material with amazing wear – tear and elastic properties. The material is considered best for sealing as it offers good resistance minerals, grease, chemicals, petrol, diesel, heating oil, vegetable oil, and fats. At high temperature, material will get harder.
- Fluoro Rubber
This material is highly characterized by its thermal and chemical resistant properties. The material has exceptional wear and tear properties and it is able to withstand even with harsh environmental conditions. The material shows good resistance against minerals, grease, chemicals, petrol, diesel, heating oil, vegetable oil, and fats.
Every time when you are operating needle roller bearings at high temperatures then certain safety standards should be followed properly. The seals made up of fluoro rubber have potential safety risks and users have to be safe to avoid unwanted dangers.