Inductive hardening

Inductive hardening, also known as induction hardening, is a process used for hardening steel. Induction is used for generating heat directly in the component. The process is immediately followed by tempering. This has the advantage of rapid, locally limited heating, and allows the targeted hardening of specific areas in the component. Härtha offers you inductive hardening for single parts and component series. Our extensive capacities allow us to rapidly complete individual requests with maximum quality. Contact us and put your trust in our professional know-how.

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The process and its advantages

Heating directly in the workpiece by inductive hardening

The heating needed for inductive hardening takes place within the component itself. This makes it possible, for instance, to restrict the hardening specifically to the interior or the exterior surfaces of a component. This is accomplished through induction. For this, a copper coil is used to generate an alternating electromagnetic field. The electrical resistance in the component causes the development of heat, which can be used to reach the specific hardening temperature.  

Hardening procedure

Unlike other hardening processes, induction hardening takes place in sequences. This means that each segment of the area to be hardened can be heated in turn by repositioning the inductor and quenching the segment using a sprinkler.
Depending on the size of the component and inductor, the workpiece can also be gradually slid through the inductor. It may also be necessary to perform a rotary motion during this process (e.g. for shafts).
The stresses in the steel are subsequently relieved at low temperature or by tempering.

Brief heating and dwell times ensure very low oxidation. Formation of the desired microstructure requires that the dwell time and hardening temperature are set in the correct relationship. This relationship depends on the type of the material, and especially its carbon content. The typical temperatures lie between 800 °C and 950 °C

The advantages at a glance

Discover some of the major advantages of inductive hardening:

  • Locally limited hardening easily possible
  • Quick processing time thanks to short process duration
  • Slight warping and minimum scale formation
  • Suitable for automation, and reproducible

Areas of application

Inductive hardening is ideally suited for components with complex geometries and tools that are exposed to extreme wear in certain places. For example, the blade of a pair of pliers is suitable for induction hardening. Further application examples include bolts, crankshafts, gear wheels, valve tappets, and rollers.

Suitable materials

Quenched and tempered steels selected for inductive hardening must have a carbon content greater than 0.3 %.
Suitable materials include:

Material number Short name Steel grade HRC
1.0503 C45 Quenched and tempered steel 48-58
1.7225 42CrMo4 Quenched and tempered steel 48-60
1.3503 100Cr6 Ball bearing steel 50-65
1.8159 50CrV4 Quenched and tempered steel 48-60
1.2826 60MnSiCr4 Collet steel 48-58

Customer specifications for the heat treatment

We are delighted that you wish to commission inductive hardening from us. To complete your order, the information required includes:

  • Material designation
  • Nominal value for the surface hardness
  • Nominal value for the hardness depth
  • Identification of drill holes near the surface
  • Is tempering also required?

For further information required, please refer to the printed order form, which we will be happy to provide.

Process locations

Refer to our location overview to learn at which Härtha locations we perform inductive hardening.