Do Not Let Your Bearing Down: Halt Corrosion before It Starts
Corrosion is a natural enemy of any rolling element. Every time that chemical reactions, acids, and vapors attack your machine bearing surface, the impact is rarely imminent until it is too late. But you cannot give up on the bearing!
The good thing is that there are a number of things that you can do to protect the bearing from corrosion. The first thing is defining the service conditions. Then, you will need to evaluate the available methods of corrosion prevention. Do not let your bearing down; here is what you should do.
Focus on performance requirements
There are a number of performance criteria that should be considered when targeting to prevent corrosion. The commonest ones include:
- The right load that the bearing should support
- The expected duty cycle
- Bearing rotation and speed
- The degree of bearing position accuracy
- What is the right lubrication?
While the performance criteria will not be directly affected by corrosive operating environment, it might be necessary to make some modifications. The type of the adopted modifications will largely rely on the nature of contaminants.
Identifying the system contaminants
The main contaminants that result in corrosion are those that contain some sort of moisture. However, they also have varying concentrations. For example, the most obvious one is water. But even water is not simple.
The protection you use against water will not be effective against oxygen-rich or iron-rich condensates. Good examples to think about at this point are acids and salts. If your bearing is exposed to them, you need the right prevention to use and in what concentrations.
Lubrication manufacturers recommend that you look beyond contaminants and factor the effect on the operating environment. Some such as high temperatures and pressure are obvious. However, others are not.
In some circumstances, dry lubricants could react with water to create sulfuric acid in the bearing surface.
Note that bearings can also be exposed to corrosion contaminants before installation, manufacturing, and shipping. It is, therefore, crucial that they are produced in moisture free environment and packaging during shipping.
The main corrosion protection options
Though there are many corrosion protection options out there, it is important to narrow down and only select the ideal option for your system.
- Lubricants: Though designed to minimize metal-to-metal wear, they can also help to protect against mildly corrosive environment.
- Seals: These are used to help keep particles away from bearings. Note that the seals might not be effective against gases or liquid contaminants.
- Protective coatings: These coatings are made from materials such as nickel and chromium and are ideal for highly corrosive environments like acid bath plants.