There is an optimal heat treatment method for each unique project and set of quality requirements.
Consider whether high frequency induction hardening is best for you, while knowing the differences from other heat treatments.
First, carburizing is performed on a large quantity in a furnace, whereas high frequency induction hardening is performed by coil on single pieces at a time.
Second is the approach toward hardening location. In carburization, low-carbon, case-hardening steel is mainly used and carbon is allowed to permeate the workpiece surface over several hours in the furnace, before it is quenched; when only hardening specific areas, anti-carburization treatment is required before furnace heating. High frequency induction hardening, on the other hand, can be conducted only on specific areas, depending on coil shape.
Third is the approach is to ensuring case depth.
Carburization case depth is adjusted by adjusting the time in the furnace—deeper case depth is achieved through a longer time in the furnace, allowing the carbon to permeate deeper. With high frequency induction hardening, on the other hand, case depth is adjusted through coil power and heating time. Adjusting hardening time by the second can lead to significant productivity gains.
In contrast, high frequency induction hardening heats the workpiece to above the transformation point, so warpage is more likely to occur (depending on the workpiece shape), but a case depth of 0.1mm to several millimeters or more can be obtained with only a few seconds to several tens of seconds of heating and cooling.
In addition, the hardness and hardening range can be fine-tuned by adjusting the coil shape, power input, cooling rate, and other factors.
As each hardening method has its own merits and demerits, the optimal method must be selected based on the purpose of hardening, as well as the size and shape of the workpiece.
The difference in case depth between the two is not as simple as "induction hardening is deep, while laser hardening is shallow.” In high-frequency induction hardening, the case depth can be controlled by changing the frequency, and depths of 1 mm or more can be easily achieved. On the other hand, laser hardening is suitable for case depths of 1 mm or less (0.3 mm to 0.8 mm) and does not require cooling. For further differences, please refer to the following link.
High frequency induction hardening is a method that utilizes coils outside the furnace to harden only specific areas, at the required depth. The major difference from general heat treatment is that the core retains the original hardness of the base material. However, to shorten the heat treatment time, a furnace coil can be used to harden the entire workpiece by high frequency induction hardening.
See the following details for selection criteria.