The surface of a steel gear made of 1018 steel (0.18 wt% C) is to be gas carburized at 927°C….

The surface of a steel gear made of 1018 steel (0.18 wt% C) is to be gas carburized at 927°C. Calculate the time necessary to increase the carbon content to 0.35 wt% at 1.00 mm below the surface of the gear after an 8.0-h carburizing time. Assume the carbon content at the surface of the gear is 1.20 wt%. D (C in _ iron) at 927°C = 1.28 × 10_11 m2/s.