For a steel alloy it has been determined that a carburizing

For a steel alloy it has been determined that a carburizing heat treatment of 15 h duration will raise the carbon concentration to 0.35 wt% at a point 2.0 mm from the surface. Estimate the time necessary to achieve the same concentration at a 6.0-mm position for an identical steel and at the same carburizing temperature.

Solution

Using the relation

X=(Dt)^1/2   for both the eqaution

Here

X1=2.0 mm

T1=15 hrs

X2=6.0 mm

to aechive the same concentration i.e D1=D2=0.35 wt %

Hence T2=135 hrs