Task 3 1.5 kg of austenite ( - iron) with 1.0 mass% (weight%) C is cooled down to 725 C. The state diagram for iron-carbon alloys is given in fig. 9.24 (10th ed.) / Fig. 11.23 (9th ed.). Use the diagram to answer the following: a)

(I)What is the proeutectoid phase?

(II) Calculate how many kg total ferrite (-iron) and cementite (Fe₃C) are formed. (III) Calculate how many kg of perlite and proeutectoid phase are formed. (IIII) Sketch and name the microstructure at 725 C.

ch Composition to 10 1600 538C 1493C 20 1400 1394" y+L 2500 1200 1147C y. Austenite 2.14 15 m 4.30 2000 1000 9120 Temperature ("A 7. Fesc 800 727" 1500 0.76 0.022 , Ferrite 600 a + Fezc Cementite (Fezc) 1000 400 2 o (Fe) 3 Composition (wt% C) 5 6 6.70