Application
Carburising
Case Hardening for Maximum Wear Resistance with a Tough Core
Carburising is the most economical process for case hardening components made from low-alloy case-hardening steels. In a carbon-rich gas atmosphere at 850–1000 °C, carbon diffuses into the surface layer of the steel. After quenching, a hard, wear-resistant martensitic surface layer is formed while the core remains tough, the ideal combination for highly stressed drivetrain components.
Precise atmosphere control is critical: the carbon potential must be exactly controlled during the carburising and diffusion phases to achieve the desired case depth and surface carbon profile.
Process Parameters at a Glance
| Parameter | Typical Range |
|---|---|
| Carburising temperature | 850–1000 °C |
| Atmosphere | Endothermic gas, propane/N₂, methanol/N₂ |
| Case depth (CHD) | 0.3–3.5 mm |
| Follow-up | Direct or reheat hardening |
Typical Materials and Components
- Case-hardening steels (16MnCr5, 20MoCr4, 18CrNiMo7-6)
- Gears, drive shafts, camshafts, pins, bushings
- Automotive transmission parts, agricultural machinery components, machine tool parts
Recommended NTH Therm Furnace Systems
- Carburising Furnace: purpose-built for atmosphere-controlled case hardening with CO/CO₂ regulation
- Chamber Furnace ICF: for smaller batches and special applications at elevated temperatures
- Quenching & Hardening Furnace: combined system for carburising and direct hardening in one cycle
Frequently Asked Questions
What is the difference between carburising and nitriding?
In carburising, carbon is introduced into the surface layer at 850–1000 °C followed by quenching to form a hard case. Nitriding introduces nitrogen at lower temperatures (480–580 °C) without quenching, resulting in less distortion but a shallower case depth.
What case depths are achievable by carburising?
The case hardening depth (CHD) typically ranges from 0.3 mm to 3.5 mm depending on process time and temperature. Longer holding times or higher temperatures increase case depth but extend cycle time.
Which atmospheres does NTH Therm use for carburising?
We offer systems for endothermic gas, propane/N₂ mixtures and methanol-cracked atmospheres. All variants are precisely controlled via oxygen probes and carbon potential regulation.