What Type of Heat Treatment Is Best?

Heat treating involves the refinement process of metals through heating and cooling. The point is to increase the strength and formability of the material. Determining the type of heat treatment for CNC and machine parts depends on its final application. Our technicians use specialized equipment to ensure that your parts will be ready for the next step. Here are six types of heat treating in Gastonia, NC and when they apply:

  • Annealing: The annealing process heats materials to an extremely high temperature and slowly cools them down. It is often performed after metal alloys are softened, and often enhances their machinability. You require annealing when materials need better hardness and chemical changes. Once done, there are usually further processes such as machining, grinding or quenching.
  • Stress relieving: Often a step within annealing, stress relieving addresses flaws in materials. Once the metal is hardened into its required strength, the stress relieving steps remove internal dislocations or defects, which leaves the metal more stable. The point is not to change the properties of the material, as changes to hardness or strength are not needed in these situations. If that occurs accidentally during the process, it is unwanted.
  • Quenching: For extra hardness, quenching is a needed process. Normally performed after CNC machining, the metal heats to a high temperature and is cooled quickly by submerging the material into water, oil or a polymer solution. The effect is a “freeze” on the material’s microstructure. Technicians choose the submersion material by how quickly they need to cool the metal. Quenching is frequently done to tool steels, since they need to stand up to the rigors of performing tasks.
  • Tempering: Often following quenching, tempering reduces hardness in materials when it is necessary. This increases its ductility while maintaining the microstructure. If a material is hardened too much, this removes any brittleness that may have developed during quenching. The result is a material that can stand up to the rigors of machining and create parts that are less likely to fail. If machine parts fail, it is often because they were quenched improperly and the technician skipped the tempering step.
  • Induction hardening: This process is similar to quenching, except for one big difference: induction hardening is applied selectively to material rather than on all of it at once. Using magnetic coils, the heat treatment matches the part’s geometry and only addresses those areas which lack strength and ductility. This allows a balance in the metal without risking the areas that already meet requirements. Like traditional quenching, this is done with water, oil or polymer, and the choice of solution depends on how quickly the material should be cooled.
  • Case hardening: These heat treatments include nitriding, nitrocarburizing, carburizing and carbonitriding, and unlike the treatments listed above, case hardening seeks to alter the material’s chemical composition. This can be necessary if a part requires a durable surface or a softer core for shock absorption and strength. It is also necessary if additional elements are required in the material, like carbon. This frequently occurs with materials that later create gears, blades and cutting tools.

J.F. Heat Treating Inc. offers expert heat treatment in Gastonia, NC to soften, harden or modify materials. Contact us today to discuss your project.

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