Consider the gas carburizing of a gear of 1020 steel at 927oC. Calculate the carbon content at 0.5mm beneath the surface of the gear at 5hr carburizing time. Assume the carbon content at the surface is 0.90% and that the steel has a nominal carbon content of 0.20%. The diffusion coefficient of C in 1020 steel at 927oC is 1.28 x 10-11m2/s.