How Do I Know Which Heat Treatment Is Best for My Parts?

Heat-treating metals to create stronger materials is a practice that goes back centuries. Today, we have a multitude of metallurgical processes to fine-tune metal for specific purposes, including annealing and case hardening in Gastonia, NC. Depending on what you’re hoping to treat, certain processes may be more suitable than others. You should consider what kind of metal you’re treating, its purpose, the environment it will be in and the stress it will be under.


Annealing describes the process of heating a metal until it’s in an equilibrium state. Generally, this changes the metal’s hardness, but it can also create localized chemical changes. Annealing is often used after machining processing.

There are several processes that fall under the annealing umbrella:

  • Quenching: This requires heating steel until its microstructure changes, then dunking it in water, oil or other coolant to keep the new microstructure in place. This can make the metal incredibly hard, but decrease its toughness.
  • Tempering: Tempering makes metal softer and more ductile, but has precise temperature and time requirements to achieve the specific result you desire.
  • Stress relieving: Stress relieving follows quenching and tempering, and is used to remove internal dislocations or defects. This makes the metal more dimensionally stable.
  • Precipitation hardening: This follows tempering and is suitable for several types of steel. It’s also known as “age hardening,” due to the time it requires.
  • Induction hardening: This process is very similar to quenching, but the metals are strategically heated. It allows critical parts to be hardened while keeping the core the same.

Case hardening

Case hardening in Gastonia, NC changes the chemical composition of the metal and focuses on its surface:

  • Carburization: This process is ideal for parts that need surface hardening, but a softer core, and involves the addition of carbon into the steel. It’s ideal for gears, blades or other cutting tools.
  • Carbonitriding: Similar to carburization, it is performed at lower temperatures. There is less distortion, but the hardening depth is also reduced.
  • Nitriding and nitrocarburizing: These processes diffuse nitrogen throughout the metal and are performed at significantly lower temperatures than carburization. The processing is done mostly on the surface level, while the core remains intact. This is ideal for long-term wear-resistant surfaces. Nitriding can be done with gas, ions or plasma, and can be performed on alloys and low carbon steels.

Annealing and case hardening services in Gastonia, NC

Need help deciding which metallurgical process is right for your parts? Ask the experts. For all of your annealing and case hardening needs in Gastonia, NC, call the team at J.F. Heat Treating, Inc. At J.F. Heat Treating Inc., we are proud to offer the full range of metallurgical and heat treatment services in our professional lab. Whether you need to harden, soften or carburize the metal, we offer completely professional service for all types of steel products, parts and machines. Contact us today to get a recommendation on which process might be right for your steel products. We look forward to working with you soon.

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