How it works
A coil emits a high-frequency electromagnetic field that induces eddy currents in the steel surface, heating just that zone within seconds.
The part is then quenched immediately (often a water spray), so the skin becomes hard martensite while the core stays tough because it never got hot.
Higher frequency means a shallower hardened case depth, so it can be tuned to the job.
Where it fits
- Shafts, pins and dowels needing a wear-resistant skin over an impact-resistant core.
- Localized zones such as thread tips, screw points or contact faces.
- Jobs needing fast, consistently repeatable (automated) cycles.
Best on medium-carbon steel—e.g. S45C, SCM440—with enough carbon to harden the surface.
How it differs from through hardening
Through hardening hardens the whole body—good when the entire part must be hard, but more prone to distortion and more brittle.
Induction hardens only the selected surface, lowering overall distortion and keeping a tough core.
The choice depends on *where* you need hardness and how the part is loaded.
FAQ
Induction vs carburizing?+
Different: induction heats medium-carbon steel that already has the carbon, while carburizing first adds carbon to the surface of low-carbon steel before hardening.
Can case depth be controlled?+
Yes—by tuning frequency, power and time, then verifying case depth with a cross-section hardness traverse.
Can very small parts be done?+
It depends on geometry and the zone to harden. Send a drawing and we will assess suitability.
