What Is Gas Nitriding?

Gas nitriding is a surface treatment for increasing a part’s surface hardness and wear resistance while maintaining the mechanical properties of the material’s core. The material is not hard all the way through, and this process greatly minimizes the risk of cracking or fracture.

Parts used in the medical, aerospace, defense, and power generation industries must be resilient and uniform to guarantee quality. The process is crucial for wear or contact surface equipment because gas nitriding enhances the surface hardness to a higher degree than some materials can reach through traditional thermal processing.

What Is the Process of Gas Nitriding?

Gas nitriding works by introducing nitrogen to the surface of a solid ferrous alloy by keeping the metal at a consistent temperature and introducing a nitrogenous gas such as ammonia.

The process of nitriding parts works through multiple steps. At Vacu Braze, our procedure generally looks like this:

1. Parts are fully machined, then sent to Vacu Braze.
2. Parts undergo traditional heat treatment, whether it’s a quench and temper in a vacuum or in an atmosphere furnace.
3. Sometimes, surface preparation with acetone is needed because parts not treated at Vacu Braze may be oily, impeding effective nitriding. Or, if parts are treated and discolored, they must be glass beaded before nitriding to ensure an even surface treatment.
4. Once prepared, the parts are loaded into the Nitrex, and the appropriate recipe is selected.
5. Vacu Braze uses two-stage nitriding to minimize the formation of a brittle white layer on the part’s surface. A dissociator is also used to allow us to nitride more challenging materials.
6. Once the part is removed from the Nitrex, some customers ask for their parts to be glass beaded to remove any white layer formation
7. The parts are hardness tested on the HR15N superficial hardness scale to check the surface hardness.
8. If requested, a case hardness profile can be performed under a microscope if the customer provides a test piece.
9. The parts are shipped back to the customer.

What Are the Benefits of Gas Nitriding?

Gas nitriding is essential for parts across multiple industries, including medical, defense, power generation, and aerospace manufacturing. There are numerous reasons to take advantage of gas nitriding, such as:

• Ensuring an exceptionally high surface hardness through precision heat treatment
• Increasing equipment’s resistance to wear
• Enhancing equipment’s anti-galling properties, which is good in poor lubrication conditions
• Minimizing distortion and deformation during heat treatment compared to carburizing or traditional hardening methods
• Stabilizing the equipment case
• Increasing the fatigue life of the equipment
• Reducing notch sensitivity
• Enhancing resistance to corrosion in many materials
• Minimizing volumetric changes
• Creating a surface that is resistant to the softening effect of heat at temperatures up to the nitriding temperature

Vacu Braze is a precision heat treatment facility in Bucks County, PA serving clients across the medical, aerospace, defense, and power generation industries throughout the United States. Our state-of-the-art facility, growing capabilities, and skilled team allow us to offer innovative solutions to companies of all sizes.

Contact Vacu Braze to learn more about nitriding and how it can benefit your production cycle.