Question 1 Carbon steel (AISI 1010) shafts of 0.1-m diameter are heat treated in a gas-fired furnace whose gases are at 1200 K and provide a convection coefficient of 100 W/m². K. If the shafts enter the furnace at 330 K, use the lumped capacitance model to estimate how long must they remain in the furnace to achieve a centerline temperature of 800 K? Use p = 7832 kg/m³, k=51.2 W/(m·K), c=541 J/(kg·K) and a = 1.21 x 10-5 m²/s. They must remain in the furnace for Physical Properties Mathematical Functions the tolerance is +/-2% S.