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Mechanical Engineering · Q199

Engineering Materials

Engineering and GATE · Mechanical Engineering · question 199

Q199

Gamma-iron occurs between the temperature ranges of

A.
400°C to 600°C
B.
600°C to 900°C
C.
900°C to 1400°C
Answer
D.
1400°C to 1530°C

Answer: Option C

Solution

Answer: Option C
Solution:
As the iron cools further to 1,394°C its crystal structure changes to a face centered cubic (FCC) crystalline structure. In this form it is called gamma iron (γ-Fe) or Austenite. γ-iron can dissolve considerably more carbon (as much as 2.04% by mass at 1,146°C). This γ form of carbon saturation is exhibited in stainless steel.