Figure 2 shows CCT curves for a eutectoid plain-C steel. What will be the final

Question

Figure 2 shows CCT curves for a eutectoid plain-C steel. What will be the final microstructures (phases present and approximate amounts) resulting from the various cooling curves shown in this diagram? (b) Which is micro structurally more stable: pearlite or spheroidite and why? (c) Compare strength and ductility of coarse pearlite, fine pearlite and spheroidite; (d) What microstructural changes happen to martensite during tempering? (e) We have a component which is pearlitie, soft and weak. Describe a procedure for strengthening this component. If instead we need to soften further the initial component, how can we do it?

Explanation / Answer

The strength of pearlitic steel was clearly reduced by annealing, even though cementite stably maintained a lamellar structure. In response, lattice strain of the ferrite phase in pearlite monotonically decreased with increasing annealing time. As a result, a good linear relationship was established between the strength and ferrite lattice strain independent of the interlamellar spacing and morphology of cementite. This suggests that the ferrite/cementite elastic misfit strain contributes to the high strength of pearlitic steel.

Related Questions

Navigate

• Browse (All)
• Browse F
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.