Question

Bonus Problem (worth 5 extra points.) You must show all your work to receive credit! 26. You are asked to improve the hardness (and strength) of a steel sample by "carburization" process. The initial carbon content (co) of the sample is 0.2 wt %. You are using a carbon rich environment (hydro- carbon gas) to set the surface-carbon content (c) at 1.0 wt %. Using the Figure 5.11, calculate the required carburization temperature to reach a carbon content of 0.4 wt % at a distance of 2 mm from the surface within 6 hours. Give answer in Degree C unit. Highlight your final answer.

Answer 1

rven 26. 04 C=4otZ - Co 0-2 wt/. , G-01 wt/. C-CO 2VD七 CS-Co 0.4-0.2 1-erf (a 2VDE 1-0.2 FO.T5 NDE. from Table

ス crf(z) O 8 O 742 O 75 O-85 r0.7707 O.15-0.7421 ひ-770 7-0-7421 ス-0-8 O-85-08 Zニ 0-814 こ0.814 2x10-3 2Dt こ0-814 Dt =1509X1O6 D (6xz600s) - 1509 X1O6

m2s from fg Ds 6.98 X 10 at 5-11 -0.8X1O3 K~1 T, 250 K