Question

Using the attached TTT diagram for 1.13 wt% C steel, name the structures present and approximate quantities after the following heat treatments: a) heat to 900°C, quench to 700°C, hold for 10 s, quench to 0°C (the iron-iron carbide phase diagram will help) b) heat to 900°C, quench to 300°C, hold for 1000 s, quench to 0°C c) heat to 900°C, quench to 100°C d) heat to 800°C, quench to 0°C (the iron-iron carbide phase diagram will help)

Answer 1

@ neat to 900°c , quench for 700°c hold for los quench to 0°C. phase will be At goo'c only austenile present after quenching to too'c and holding for 10s. Some austerile will transform into Comentile as proeutectoid phase. Them quenching to se, remaining ausknik wil townsform into maskensite. Hence, structure will comast ob Cementik and moetensile heat to 900°c, quench to 30oC, had for 1000s, quench to 50%. heat At goo'c, only austenite phase will be present quenching will transformed the to 300'c and holding those looos 50% anglenite into balsire. Then quenching to o'c will transform semaining sot. auskenike into mosteosile. Hence, struchose win consist of 50 y. Bainik and sor. martensile. to 900°c quench to 100°c At goo'c only austenile phase will be present. to 100'c , 754. of austenite phase will transfoom into markasite and remaining a5%. of austenite be toansform. struchine consist of 854. auslenire, and 76% martensile heat to 800'c quench to o'c At 800'c , only austenite phase is present. Quenching to do wiu trome form all ausknik into morstensfle . Hence, Morskastre structure will be produced. Quenching will not Hence