Induction Hardening of Forged Components
Induction hardening solves a problem that through-hardening cannot: making a surface wear-resistant while leaving the body tough. It heats only a controlled surface layer, then quenches it before the heat reaches the core.
- Case Hardness
- 55 – 60 HRC
- Case Depth
- 1 – 5 mm typical
- Minimum Carbon
- ~0.35%
- Distortion
- Low, core unaffected
- Suitable Grades
- EN8, EN9, SAE 1045, EN19, 42CrMo4
- Applications
- Shafts, cams, pins, gear teeth, rods
Induction Hardening of Forged Components at a glance
Quotable facts from Avadh Techno Forge, Gundasara, Gondal, Rajkot.
- Case Hardness: 55 – 60 HRC
- Case Depth: 1 – 5 mm typical
- Minimum Carbon: ~0.35%
- Distortion: Low, core unaffected
- Suitable Grades: EN8, EN9, SAE 1045, EN19, 42CrMo4
- Applications: Shafts, cams, pins, gear teeth, rods
How It Works
A high-frequency coil induces eddy currents in the surface layer, heating it above the critical temperature in seconds. Immediate quenching transforms only that layer to martensite, leaving the core in its original tough condition.
- Heats only the surface layer
- Seconds, not hours
- Core stays tough and unaffected
- Case depth set by frequency and time
Case Depth Control
Higher frequency gives a shallower case; longer heating gives a deeper one. Typical depths run 1–5 mm at 55–60 HRC, adjusted to the contact stress the surface will actually experience.
Distortion and Its Limits
Because the core never reaches transformation temperature, distortion is far lower than through-hardening. The limits: the part must be a suitable geometry for coil design, and the material must have enough carbon — roughly 0.35% minimum — to form martensite.
Topics covered on this page
- induction hardening forgings
- surface hardening forged parts
- induction hardening case depth
- selective hardening guide
Based on work carried out at our own forging plant at Gundasara, Gondal, Rajkot — operating since 2008.
Questions Answered
What is induction hardening used for?
+
Giving a hard, wear-resistant surface to shafts, cams, pins, gear teeth and cylinder rods while keeping the core tough.
How deep is the hardened case?
+
Typically 1–5 mm, set by coil frequency and heating time to suit the contact stress.
Which steels can be induction hardened?
+
Those with roughly 0.35% carbon or more — EN8, EN9, SAE 1045, EN19 and 42CrMo4 all respond well.
Does it cause distortion?
+
Much less than through-hardening, because the core never reaches transformation temperature.