Process Conditions
Treatment Type
Treatment Temperature T
920 °C
Treatment Time t
4.0 h
Surface Carbon Cs
1.10 %C
Core Carbon C0
0.20 %C
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Effective Case Depth [mm]
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Surface Hardness HV
—
Core Hardness HV
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Cost Index
—
Fatigue Improvement
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Diffusivity D [mm²/s]
Cross-section / Case Depth Diagram
Carbon Profile C(x)
Hardness Profile HV(x)
Theory
Carbon profile (erfc diffusion solution): $C(x,t) = (C_s - C_0)\,\mathrm{erfc}\!\left(\dfrac{x}{2\sqrt{Dt}}\right) + C_0$
Diffusivity (Arrhenius): $D = D_0 \exp\!\left(-\dfrac{Q}{RT}\right)$
Carbon to hardness (simplified): $HV \approx 20 + 38 \times \%C + 50 \times (\text{alloy factor})$
Electroplating (Faraday's law): $\delta = \dfrac{M \cdot I \cdot t}{n \cdot F \cdot \rho \cdot A}$ [m]
Shot peening residual stress depth: $z_p \approx 0.5 d_{shot}\sqrt{HV_{shot}/HV_{part}}$
CAE Integration: Case depth and hardness profile are used as depth-dependent material input for FEM fatigue analysis (FEMFAT, nCode). Residual compressive stress is applied for mean stress correction in Goodman/Haigh diagrams.