What is ferrite very low solubility of carbon?

What is ferrite very low solubility of carbon?

Octahedral interstitial site of BCC ferrite is much smaller for carbon than that of FCC austenite. This is why solubility of carbon in ferrite is much smaller than solubility of carbon in austenite.

What is the solubility of carbon in ferrite?

The iron – Fe3C phase diagram indicates that the maximum solubility of carbon in ferrite occurs at the eutectoid temperature of 727 C and is 0.022 wt % C in the iron matrix.

Is carbon more soluble in austenite or ferrite?

Carbon is generally more soluble in austenite than ferrite. Reason is carbon atoms occupy octahedral interstitial sites in these crystals. Octahedral in FCC is bigger than tertrahedral.

What is the maximum carbon solubility of carbon in ferrite?

0.035%
Ferrite, while less dense than austenite, has no such locations for carbon solute, and the maximum solubility of carbon in α ferrite is only 0.035% at 732 °C. At carbon levels beyond this small solubility limit, the stable phases are ferrite (nearly pure iron) and cementite (or austenite).

What is the maximum solubility of α ferrite?

0.022 wt%
➢ α-ferrite – solid solution of C in BCC Fe • Stable form of iron at room temperature. The maximum solubility of C is 0.022 wt%. Transforms to FCC γ-austenite at 912 °C.

What is the iron carbon diagram?

The Fe – C diagram (also called the iron – carbon phase or equilibrium diagram) is a graphic representation of the respective microstructure states of the alloy iron – carbon (Fe-C) depending on temperature and carbon content. To explain this diagram, an introduction about metal structures and pure iron must be done.

Why does austenite have more carbon solubility?

The total open space is shared by more number of sites. Therfore interstitial gap in BCC is much smaller than that of FCC. This is why carbon which occupies interstitial site has higher solubility in austenite (FCC).

What is the solubility of α ferrite at 0oc?

What is the solubility of α ferrite at 0oC? Explanation: α ferrite is an interstitial solid solution of carbon in a BCC crystal lattice. It has a solubility of 0.02% at 723oC and decreases to 0.005% at 0oC.

What is maximum solubility of carbon and temperature range that α ferrite exist?

What is maximum solubility % of carbon and temperature range that α-ferrite exist? Explanation: Interstitial solid solution of C in BCC iron. Max solubility of C is 0.025% and it exists from 273°C to 910°C.

How do you read an iron carbon diagram?

The weight percentage scale on the X-axis of the iron carbon phase diagram goes from 0% up to 6.67% Carbon. Up to a maximum carbon content of 0.008% weight of Carbon, the metal is simply called iron or pure iron. It exists in the α-ferrite form at room temperature.

Does austenite have a higher carbon solubility?

Whereas in BCC these are nearly same. Therfore interstitial gap in BCC is much smaller than that of FCC. This is why carbon which occupies interstitial site has higher solubility in austenite (FCC).

Why is solubility of C in ferrite only 0.025%?

Octahedral interstitial site of BCC ferrite is much smaller for carbon than that of FCC austenite. This is why solubility of carbon in ferrite is much smaller than solubility of carbon in austenite. Possible maximum carbon content in austenite may be 2%.

Why is carbon more soluble in austenite than ferrite?

Whereas in BCC these are nearly same. The total open space is shared by more number of sites. Therfore interstitial gap in BCC is much smaller than that of FCC. This is why carbon which occupies interstitial site has higher solubility in austenite (FCC).

Why is the solubility of carbon so low?

That is why the solubility of carbon is less. The maximum solubility is 0.0218% at 723′ C and at room temperature the solubility is only 0.008%. The carbon atom is small for substitution and too large for interstitial solid solution. Ferrite is soft and ductile. It is magnetic under 770’c.

Why does carbon occupy more interstitial sites than ferrite?

Carbon occupies interstitial sites of iron mainly the octahedral sites because in FCC (austenite) , these octahedral sites are larger than in BCC (ferrite) , irrespective of the more number the octahedral sites in bcc (ferrite) than fcc (austenite), so mainly it zeros on the size of the octahaderal voids.