The Pros and Cons of Induction Hardening

Induction hardening is a type of heat treating method in which you selectively and rapidly harden a metal surface. In the process, you place a copper coil that carries an alternating current near the part, but not directly touching it. Heat is generated close to the surface with eddy current and hysteresis losses. Then, a water-based quench (often with a polymer addition) gets directed at the part or submerged, resulting in the structure being transformed into martensite, a significantly harder structure than what previously existed.

Modern induction hardening in Gastonia, NC is most frequently performed with a scanner. In this method, the part is held between centers, rotated and then sent through a progressive coil, which generates heat and quench alike. The quench is directed below the coil, meaning any area of the part is being rapidly cooled right after it’s heated.

Benefits of induction hardening

Here’s a quick overview of some of the benefits of this process:

  • Increased strength and fatigue life: The softer core and residual compressive stress at the surface creates increased overall strength and fatigue life. This is a result of the hardened structure at the surface taking up more space than the core and the previous structure.
  • Tempering: Parts can be tempered after induction hardening, which allows you to customize the hardness level according to your needs. The more you temper, the lower the hardness will be, and the lower the brittleness will be as well.
  • Minimal distortion: The induction hardening process results in relatively minimal distortion to a piece of metal. Other hardening processes tend to feature a lot more warpage than what you get in the induction hardening process.
  • Low cost: With induction hardening in Gastonia, NC, you can use lower-cost steels than you can in other types of hardening methods. This allows you to save money on the overall process.
  • Wear resistance: The wear resistance of the parts you work on will increase significantly with the induction hardening process, assuming the material had either already been annealed or treated so it was in a softer condition.

Drawbacks of induction hardening

There are a few disadvantages of the induction hardening process to consider as well:

  • Distortion: Distortion levels do tend to be larger in induction hardening than they are in processes such as ion or gas nitriding as a result of the rapid heating and quenching process and the martensitic transformation that occurs as a result. However, this distortion is still less than what you’d get from conventional heat treatments.
  • Cracking: There is a greater likelihood of cracking in induction hardening than there is in other types of heat treatments.
  • Material limitations: Not all types of materials can be put through the induction hardening process, so it’s not quite as versatile as some other types of heat treatments.

For more information about the various pros and cons associated with induction hardening in Gastonia, NC, we encourage you to contact J.F. Heat Treating Inc. today with any questions you have about the services we provide.

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