Oil Impregnated Parts: How Are They Made?

Oil-impregnated parts have been around since about the 1930s as a component part in the automotive industry. And today, many people use them successfully and find that they are a great addition to their project needs. Yet, others just don’t quite understand what they are or what they can do for them. 

These oil-impregnated parts can be very beneficial so they are worth talking about. Let’s take a look at what they are and how they are made. 

What Are Oil Impregnated Parts? 

In a nutshell, oil-impregnated parts, such as bushings and bearings, are designed for the main purpose of being self-lubricating. The body is impregnated with a lubricating oil, hence how it gets its name. Then, in turn, this works to improve lubrication as the rotating axis that runs through the middle of the bearing begins to rotate. 

Oil-impregnated bronze bushings handle low to moderate loads, but they do very well in handling high-velocity applications. Another perk of these parts is that they are able to handle a wide range of temperatures, from 10 degrees all the way to 220 degrees. 

They may not be used for all applications, but these oil-impregnated parts can be very effective where they are. And consumers benefit due to their affordability – and the reduced need to add lubricant or routinely maintain the bushing. 

How are Oil Impregnated Parts Made? 

Oil-impregnated bronze bushings are made using a powder metal process. And you may be surprised to know that there are quite a few steps in creating this low-cost, high-quality part. Below is an overview of this process. 

Blending and Briquetting

The very first step that happens in this powder metal process is actually combining the different metal alloys or powders together with lubricants so that you can obtain the perfect mixture. It is then compressed in a die at pressures ranging from 10 to 45 tons per square inch. The die is, essentially, the size of the bushing that is being created.


The metal particles have to bond together and they best do this using heat. This is done in a furnace and at controlled temperatures that will bond the particles together without melting the metal. 

This is a very important part of the process – and is crucial to oil impregnation. Even though sintering itself will make the metal less porous, this is controlled through the process so that the metal has a porosity level at about 25%. This means it has enough tiny pores to handle the oil impregnation. 


Repressing is the final pressing of the sintered metal. This is when the bushing is given its desired size, meeting proper measurements, as well as physical properties. It is calibrated to meet the required tolerances. 


Once the bushing reaches this stage, it is impregnated with oil that is forced into it. All the pores become filled with lubricant. As the final step of the process, the bushing is then heat treated so that it retains the oil as well as its strength. 
Atlas Bronze is a brass bronze supplier that offers a wide range of products to meet your metal application needs, including oil-impregnated parts.

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