Can anyone help? I am trying to solve the maths of the carburizing
process.
I have been told that the temperature is 1100K the depth of carbon

penetration is 100microns and it took ninety minutes but i want to
calculate how these figures were achieved. Is there anyone who can
show the formulas (Arrhenius's Law)used and where the data is supplied
to carryout the calculations.
Cheers
Mark

Yep, I can help:
D = D0 * exp(-Qd/RT), where D = diffusion coefficient, Qd = activation
energy, R = gas constant (8,31 J/mol*K), T = abs. temperature, D0 = a
material constant.
Examples:
D0 for Carbon in alfa-ferrit: 6,2e-7 m^2/s and D0 for Carbon in
gamma-ferrit: 2,3e-5 m^2/s.
Qd is respectively 80 kJ/mol and 148 kJ/mol.
Fick's first law: J = -D* dC/dx, where dC/dx is you concentration
gradient, J = diffusion flux (kg/m^2*s or atoms/m^2*s)
Fick's second law: dC/dt = D * d^2C/dx^2 .... and you could probably
also find use for the error function solution:
Cx - C0 / (Cs - C0) = 1 - erf(x/(2*sqrt(Dt)) ), where Cs = concentration
at surface/interface, C0 = beginning concentration and C0 > Cx > Cs
I think we need some additional information in order to calculate your
problem...
Med venlig hilsen / Best regards
Martin Jørgensen

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