Carburizing and Its Benefits

Carburizing is the most common surface hardening technique for heat treatments in Gastonia, NC.  It works by adding carbon into a low-carbon steel alloy in order to produce a high-carbon steel surface. You will likely require this technique for steels with less than 0.25 percent carbon. This process is also called case hardening, and it adjusts steel to maintain its durability without removing properties that are also needed for a particular application. Here is an overview of carburizing and what it can offer for your industrial equipment or machine shop.

Understanding the carburizing process

The process begins by heating steel parts in a pit furnace or sealed atmospheric furnace. After reaching a certain temperature, which depends on the original condition of the steel and its future use, carburizing gases are introduced into the furnace. Heating continues until the right amount of surface hardening has been achieved.

Components are then slowly cooled for quench hardening or quenching into oil. The oil quenching is used to minimize distortion when the components do not require much adjustment. Further quench hardening follows if the component needs a higher tolerance level. Again, this is a customized approach that depends on the future applications of the steel or component.

Results of carburizing

Carburizing increases resistance to wear by creating a strong shell while maintaining a softer interior. It is often performed after the parts are machined so when they are put to use, they remain durable. Components that are oddly shaped often benefit most from carburizing, as the material needs to be soft while molded, but, once done, needs to be set into a harder framework before use. The carburizing process basically adds a protective layer.

The end product after carburizing is measured by case depth, which is the thickness of the carbon shell. Case depth is measured in inches.

Applications of carburizing

Case depth varies by application. A shallow case depth up to 0.02 inches is used for low to moderate applications and most often applied to delicate machine parts that need to be replaced frequently. Industrial gears require a deeper case depth of 0.02 to 0.06 inches to withstand heavier loading. For the heaviest crushing loads that require shock resistance, including mill gearing, rollers and bearing surfaces, the case depth is 0.06 to 0.25 inches.

High resistance results from any case depth. A thicker case depth does not necessarily mean it will work better for a given purpose. For example, small machine parts that often require a shallow case depth can be too heavy or not pliable enough if that element is produced at a higher value. That adds new potential for machinery failures that go beyond simple wear and tear. It is important to realize that durability depends on the balancing of the application and strength, not just the number assigned for case depth.

J.F. Heat Treating, Inc. offers carburizing for your various steel components, as well as a variety of other heat treatments in Gastonia, NC. If you are unsure as to case depth, call us today to discuss your industry applications so we can start the appropriate heat treatment you require.

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