4. A bearing steel with 1.2 wt.% C is analyzed for its microstructure after anne

ID: 1856918 • Letter: 4

Question

4. A bearing steel with 1.2 wt.% C is analyzed for its microstructure after annealing

heat treatment. a) Write down the phase reaction that occurs in this steel at

727oC.

b) What kind of microstructure will be found at room temperature?

c) Analyze for phases present at 100 degrees above the reaction

temperature, for their compositions and amounts in the steel.

d) How much pro-reaction phase will be found in the steel? What is its

composition?

e) How much of the reaction product mixture is formed? What is its `

composition?

f) What are the fractional amounts (relative fractions) of the two

phases in the two phase mixture?

g) How much actual amounts of the two phases are present with

respect to the alloy in the two phase mixture?

a)austenite+cementite converts into +cementite

b)At room temperature, the microstructure consists of lamellae of pearlite and cemntite lining along the grain boundary.

c)phases present at 827c austentite+cementite

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