With no carbon present, austenite starts to form at which temperature

With no carbon present, austenite starts to form at which temperature

• A. 727C
• B. 910C
• C. 540C
• D. 1000C

Answer: (B)

When heating pure iron (no carbon), the ferrite-to-austenite transformation occurs at about 912°C, so austenite starts forming around 910°C. The other temperatures relate to different phase changes (eutectoid transformation around 727°C, other transformations near 540°C, etc.), but for 0% carbon the onset of austenite is closest to 910°C.

When heating pure iron (no carbon), the ferrite-to-austenite transformation occurs at about 912°C, so austenite starts forming around 910°C. The other temperatures relate to different phase changes (eutectoid transformation around 727°C, other transformations near 540°C, etc.), but for 0% carbon the onset of austenite is closest to 910°C.