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What happens during the peritectic reaction phase change?
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Liquid and δ-iron transform into γ-austenite during the peritectic reaction.
What characterizes the hyper-eutectic transformation?
Occurs from 4.3% to 6.67% carbon content.
Describe the hyper-eutectoid transformation.
Occurs with 0.8% to 2% carbon, forming after the eutectoid point.
What is the purpose of key horizontal lines at the peritectic, eutectoid, and eutectic points?
They indicate phase boundaries and transformation temperatures and carbon percentages.
What is the role of pearlite in the iron-carbon phase diagram?
Pearlite is the mixture formed during the eutectoid transformation, consisting of α-ferrite and cementite.
What are the axes used in drawing the iron-carbon phase diagram?
The X-axis represents the weight percentage of carbon, and the Y-axis represents temperature in °C.
Identify the phases formed during the eutectoid transformation.
The eutectoid transformation forms pearlite, a mixture of α-ferrite and Fe₃C (cementite).
Explain the hypo-eutectic transformation.
Occurs between 2% to 4.3% carbon content.
At which point is steel categorized based on carbon content?
Steel is categorized up to 2% carbon content.
At what temperature and carbon content does the eutectic reaction occur?
The eutectic reaction occurs at ~1147°C with 4.3% carbon.
What is ledeburite, and how is it formed?
Ledeburite is a mixture of γ-austenite and cementite, formed during the eutectic reaction from liquid.
Describe the eutectoid reaction in the iron-carbon diagram.
γ-austenite transforms into α-ferrite and Fe₃C (cementite) at about 723°C with 0.8% carbon.
What is the significance of the liquidus line in the iron-carbon diagram?
The liquidus line represents the boundary where the phase is 100% liquid.
What is the carbon content and temperature for the peritectic reaction in the iron-carbon diagram?
0.18% carbon and occurs at approximately 1493°C.
Define the hypo-eutectoid reaction.
Occurs with less than 0.8% carbon, forming before the eutectoid point.
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