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Grinding Nitrided Parts: When Is It Necessary and Why?

  • Writer: redesiht
    redesiht
  • Sep 9
  • 2 min read

Plasma Nitriding: Minimal Distortion, Minimal Grinding


Two precision-machined ring gears after plasma nitriding, demonstrating perfect fit and minimal need for grinding nitrided parts.
AI-generated image of two ring gears showcasing precise fit after plasma nitriding, highlighting minimal distortion and reduced need for grinding nitrided parts.

One of the key advantages of plasma nitriding is that it operates within a ferritic temperature range (350°C – 600°C / 662°F – 1112°F). This means the process does not cause phase transformations like conventional heat treatments (e.g., quenching and tempering). Instead of relying on rapid heating and cooling, plasma nitriding is a diffusion-based process, where nitrogen atoms penetrate the metal surface without causing significant dimensional changes or internal stresses.

Because of this, grinding nitrided parts is rarely needed. However, there are specific cases where it may be recommended to achieve precise dimensional control or surface quality


Why Do Nitrided Parts Tend to Grow?

Although plasma nitriding does not cause shrinkage or deformation, parts may experience slight dimensional growth. This occurs because nitrogen atoms diffuse into the metal matrix, and to accommodate them, the material expands slightly.

If a company has an in-house plasma nitriding system, it can precisely measure how much parts grow in each cycle. With this information, it is possible to pre-machine parts with slightly smaller dimensions, compensating for growth and eliminating the need for post-nitriding grinding.


When Is Grinding Nitrided Parts Necessary?


1.  Surface Roughness Correction

Depending on the material and process parameters, plasma nitriding can increase surface roughness. If a smoother finish is required, a light grinding operation (removing just 2 to 3 microns) is usually enough to restore the desired surface quality.



2.  Removing the White Layer

The white layer is the outermost layer formed during nitriding. While it is very hard, it is also brittle, and in some applications, it is recommended to remove it.

In plasma nitriding, it is possible to adjust the process recipe to prevent excessive white layer formation. In industries like aerospace, where strict surface integrity is required, this can be controlled using specialized aerospace-grade process packages. These systems include mass flow controllers (MFCs) with redundant regulation, allowing precise nitrogen flow adjustments to minimize or even eliminate the white layer without the need for post-nitriding grinding.



📌 Learn more: Discover which ION HEAT plasma nitriding systems can be upgraded with the Aerospace Package for NADCAP compliance! https://www.ionheat.com/glowtech-plasma-nitrider


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