What is the minimum austenitizing temperature and the minimum time to carburize and quench a 1018 steel gear to a hardness of HRC 60 at a depth of 0.045 inches. Temperature (C) Hardness (Vicken) 900 800 700 600 0 1100 1000 900 800 700 600 500 400 300 200 100 a+y 0.20 0.5 Composition (wt% C) 0.40 6 hrs at 850C b 2 hrs at 850C y+ FeC 727C Martensitic structure (qunched) 12 hrs at 727C 2 hrs at 727C a + FezC Partic structure air-cooled) 1.0 f Spheroidized carbide structure 0.60 0.80 Carbon (%) 1.00 1.20 65 60 50 40 30 20 10 Hardness (Rockwell C Carbon (%) 1.40 1.20 1.00 0.80 0.60 0.40 0.20 0 0 2h Copyright Man Pers 1.6% CH4 6 12 24 20 40 60 80 100 120 140 Distance bely surface (0.001) in. Mandbook vol 2 Heat Treating the