Answer:
t2 = 256 hours
Explanation:
Given data:
Carbon concentration ( C ) at 1.2mm from surface, C = 0.38 wt%
Duration( t ) of heat treatment for 0.38wt% at 1.2mm = Â 9-hr
Estimate the time (in h) necessary to achieve the same concentration at a 6.4 mm
Assuming same concentration of 0.38wt% Â we will apply Fick's second law for constant surface concentration
attached below is the remaining part of the solution
x1 = 1.2 mm
x2 = 6.4 mm
t1 = 9-hr
t2 = ?
t2 = [tex](\frac{6.4}{1.2} )^{2} * 9[/tex] Â = 256 hours