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capabilities > Heat Treating > Carbonitriding


Carbonitriding is an ideal process for low-carbon, low-alloy steels that need case hardening.

Case Hardening with Carbonitriding

Carbonitriding is a case hardening method that is carried out at temperatures between 1,550 and 1,650°F, which is slightly lower than the temperature used for carburizing (around 1,700°F). Treated parts are usually then oil quenched, which helps reduce the risk of distortion. The case formed generally measures between 0.13 mm and close to 1 mm and surface hardness in these parts can range from 55–62 HRC.

Benefits of Carbonitriding

The key benefit of carbonitriding is to produce a hard and wear-resistant case on steel parts. It allows steels with relatively low hardenability to achieve the hardness characteristics of higher-grade materials. To sum up, here are the main benefits of this process:

  • Greater case depth when compared to nitrocarburizing
  • Increased fatigue strength
  • Enhanced wear resistance
  • Parts can maintain hardness at elevated temperatures

Carbonitriding Applications

This process is used to harden surfaces of parts made of cost-effective and easily-machined steels, such as:

  • Automotive stampings
  • Wood screws
  • Gears and shafts
  • Pistons
  • Tooling and dies
  • Rollers and bearings

Why Case Harden with Paulo

We measure the composition of the atmosphere in our belt furnaces at multiple locations within the furnace throughout the heat treatment process, specifically to ensure that parts are exposed to the proper amount of nitrogen. When too much nitrogen is present during carbonitriding, it can cause porosity, which degrades the value of the parts and negatively impacts the hardness. The results of all hardness tests we perform are also automatically captured, and data is stored in our PICS system. This lends greater visibility and traceability to the quality of your parts when you choose Paulo as your provider. 

Trust your parts to Paulo.

Are you facing challenges with your current heat treatment provider or have a new project coming up? We’re ready to help. Connect with a Paulo expert today!

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