The Working Principles of Nitriding and Its Benefits

11 January 2022

Heat treatment is the process of heating metal workpieces without reaching their molten or melting stage. After heating them, they are cooled in a controlled way so they can obtain the needed mechanical properties. Some heat-treated workpieces may become more malleable, while others can become stronger. Metal workpieces can also become more ductile or resistant to elements.

There are a lot of heat treatment techniques that can be conducted by manufacturers to ensure that they obtain their needed products. Some of these techniques are annealing, precipitation strengthening, case hardening, carburising, quenching, tempering, and normalising.

Another heat treatment technique that is being conducted by manufacturers today is nitriding. Nitriding is a heat treatment technique that can generate case-hardened products by applying nitrogen.

The Processes of Nitriding

As mentioned earlier, nitriding is a heat treatment process that can generate products with case-hardened surfaces. Through the infusion of nitrogen, products are expected to obtain increased surface hardness. But before carrying out the nitriding process, the workpieces should be hardened, quenched, and tempered first to ensure they possess a uniform structure. The workpieces must also be free from any oils, grits, and others through abrasive cleaning or vapour degreasing.

The whole process of nitriding depends on its type.

  • Gas Nitriding: The gas nitriding process is conducted by heating metal to a suitable temperature while holding it in contact with ammonia or other nitrogenous gases. Once the nitrogenous gases come into contact with the surface of the heated workpiece, they often break down into nitrogen and hydrogen. The nitrogen subsequently diffuses and generates a nitride layer.
  • Plasma Nitriding: Plasma nitriding, on the other hand, heats the metal surface of a workpiece through the plasma discharge of reaction gases. The same discharge can also supply nitrogen to the surface of the workpiece. The plasma discharge of reaction gases is comprised of highly active gas with ionised molecules.
  • Salt Bath Nitriding: Salt bath nitriding, ultimately, is conducted through maximising molten salt in providing nitrogen to the surface of a workpiece. Through this process, the workpiece is submerged into a preheated molten cyanide salt bath. The high concentration of nitrogen in the bath often works with iron, providing the workpiece with a dependable iron nitride thin outer surface.

Main Benefits of Nitriding

No matter what type of nitriding one has to carry out, all nitriding processes are expected to provide excellent advantages on products.

One of the advantages of nitriding processes is that they can process workpieces very quickly. They likewise do not require a lot of energy to carry out and finish the operations. Nitriding processes do not also need extremely high temperatures to generate reliable products. They do noteven generate pollution and emit toxic wastes to the environment.

As for the products, they are expected to gain significant improvements over their fatigue properties, surface, and hardness. Products that undergo nitriding processes can boast a uniform surface, a high surface hardness, and a minimised distortion. They also have improved corrosion resistance.

To know more about nitriding, you can call us at Alpha Detroit Heat Treatment.

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