Common Steels Used for Induction Hardening
A guide to materials that respond best to induction hardening and their ideal applications.
What Makes a Material Suitable for Induction Hardening?
A steel is suitable for induction hardening if it has:
- Adequate carbon content (0.35–0.55%) for forming martensite upon quenching.
- Alloying elements (like Cr, Mo, Ni, Mn) that enhance hardenability and toughness.
- Stable microstructure that can be consistently heat treated and quenched.
Materials outside this range may not achieve desired hardness or may distort after heat treatment.
Most Common Induction Hardening Materials
1. EN8 (C40 or AISI 1040) – Medium Carbon Steel
Composition: 0.35–0.45% Carbon.
EN8 is a go-to steel grade for Ludhiana’s automotive and agricultural OEMs, offering both machinability and durability.
2. EN19 (AISI 4140) – Alloy Steel
Composition: Chromium-Molybdenum (Cr-Mo) alloy steel with 0.40% Carbon.
EN19’s versatility makes it one of the most widely used steels for induction hardening job work in Punjab, especially in gear and shaft manufacturing.
3. EN24 (AISI 4340) – Nickel-Chromium-Molybdenum Steel
Composition: 0.40% Carbon with Ni, Cr, and Mo.
EN24 is ideal for heavy engineering and transmission applications where both surface wear resistance and core strength are required.
4. 4140 – Chromium-Molybdenum Steel
Composition: Similar to EN19 (0.40% Carbon, Cr-Mo base).
4140 offers reliable heat treatment consistency, especially in precision-engineered gearbox and spindle components.
5. 4340 – Nickel-Chromium-Molybdenum Steel
Composition: 0.40% Carbon, 1.8% Nickel.
4340 is preferred for high-performance industrial applications and critical rotating parts in machinery.
6. 20MnCr5 – Case Hardening Steel
Composition: 0.20% Carbon, 1.25% Manganese, and 1% Chromium.
20MnCr5 is the industry-standard material for precision gear and pinion induction hardening in automotive and tractor industries.
7. Tool Steels (D2, H13, M2)
These steels are used for specialized tooling in forging and manufacturing industries across Punjab.
| Material Grade | Typical Application | Hardness After Induction |
|---|---|---|
| EN8 | Shafts, axles, couplings, crank pins | 50–55 HRC |
| EN19 (AISI 4140) | Gears, shafts, connecting rods, crankshafts | 52–58 HRC |
| EN24 (AISI 4340) | Transmission shafts, gears, axles, heavy-duty spindles | 55–60 HRC |
| 4140 | Gears, rollers, and automotive shafts | 52–58 HRC |
| 4340 | Axles, crankshafts, and aircraft parts | 55–60 HRC |
| 20MnCr5 | Gears, pinions, and shafts for transmissions | 58–62 HRC |
| Tool Steels (D2, H13, M2) | Dies, punches, cutting tools, and forming molds | 58–64 HRC |
Conclusion: Material Matters in Induction Hardening
The success of induction heat treatment depends as much on the material composition as on the process itself. At Thakur Induction, we combine scientific metallurgy with modern induction systems to ensure every material grade achieves its maximum performance.
Looking for Material-Specific Induction Hardening?
Contact Thakur Induction for custom heat treatment services for all steel grades.