There are multiple different options in heat treating of metals, and it can be confusing for those unfamiliar with all the processes to understand why one may be a superior option to others.
An option for heat treating, specifically for case hardening, which may not be considered by many, outside of the industry, is nitrocarburizing. This process, along with carbonitriding, is called case hardening as they use carbon and nitrogen, or just one or the other, to penetrate the surface and create a layer.
In this specific process, the chemical changes occurring through the application of the carbon and nitrogen, or one or the other element, create a hard shell or case which is just on the surface. This chase is actually two layers, a compound layer, and a diffusion layer or zone.
The Process
With nitrocarburizing, both carbon and nitrogen are used to create the surface case on the part. There is a higher percentage of nitrogen used than will be found in basic carbonitriding, which has both an impact on the durability of the part as well as the aesthetics of the part or component.
There are two types of nitrocarburizing. One is austenitic, which means the temperature is maintained at a higher temperature and results in a heavier or deeper diffusion zone under the compound layer. With this additional protection, the case developed is harder and will stand up to high wear, corrosion and still have virtually no distortion of the part or component during the process.
The Ferritic process creates a slightly thinner case, but it is done a much lower heat, which means it is a very fast process with ideal aesthetic results in addition to the hardened surface. It can be used as an alternative to chrome plating that is faster but still allows for rust prevention and corrosion resistance.
