V.S. Heat Treatment
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V.S. Heat Treatment
Heat treatment & metal finishing experts
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Two ways to diffuse elements into the surface of low-carbon steel on a continuous mesh-belt line — they differ in temperature, case depth and distortion.
Carbonitriding vs Carburizing
Carburizing diffuses only carbon at high temperature (~880–950°C) for a deeper hard case (about 0.3–1.5 mm and up), suited to loaded parts needing a deep case. Carbonitriding diffuses carbon AND nitrogen at a lower temperature (~780–870°C) for a shallower case (about 0.1–0.75 mm); the nitrogen raises hardenability so thin parts harden with a milder quench, with less distortion and good wear — ideal for screws, nuts and small parts on a mesh-belt line.
| Decision factor | Carbonitriding | Carburizing |
|---|---|---|
| Diffused elements | Carbon + nitrogen | Carbon only |
| Typical temperature | About 780–870°C (lower) | About 880–950°C |
| Typical case depth | About 0.1–0.75 mm (shallower) | About 0.3–1.5 mm and up |
| Surface hardness | About 58–64 HRC | About 58–62 HRC |
| Distortion | Lower (lower temp, milder quench possible) | Slightly higher (higher temp) |
| What the nitrogen adds | Raises case hardenability + some wear/corrosion resistance | No nitrogen |
| Best for | Screws, nuts, thin small parts, shallow case, low distortion | Loaded parts needing a deep case |
| Watch-out | Retained austenite if nitrogen is too high | Control case depth and carbon potential |
Choose carbonitriding for screws, nuts and thin small parts that need a wear-resistant skin with controlled distortion and a modest case depth — it is the best fit for high-volume small parts on a continuous mesh-belt furnace.
Choose carburizing when you need a deeper hard case for parts under heavier contact or wear, accepting the higher process temperature and slightly more distortion.
Carbonitriding usually suits small, thin parts: it runs at a lower temperature with less distortion and a shallower case, ideal for high-volume screws and nuts on a mesh-belt line. Carburizing gives a deeper case for more heavily loaded parts.
It runs cooler (about 780–870°C versus 880–950°C) and the added nitrogen raises case hardenability, so thin parts can harden with a milder quench — which means less distortion.