3. [5 pts] At a temperature slightly higher than 727C, how much (in kg) of austenite (y) is there in a 81 kg of AISI1040 steel (plain carbon steel of 0.4% carbon by weight)? 1600 (Ferrite) 1538C 1495C 1400 1394C y+liquid 1100 Liquid 1000 2500 900 2000 Temperature (C) 1200 1148C y (austenite) 2.11% 4.30% 2000 1000 912C Y+ cementite a+y -Detail view 1500 800 727C F Temperature (C) 800 Y+FeC 1500 a+y 727C 700 600 0.77% 0.022% 600 a + cementite Ferrite -Fe C-1000 a (ferrite) 1000 Cementite (Fe C). 500 400 2 3 4 5 6 6.67 400 Carbon (% by weight) 0 (a) a + Fe3C 0.5 1.0 1.5 2.0 2.5 Carbon (% by weight) (b)