Microstructure formation during solidification

This article provides answers to the following questions, among others:

  • What is steel made of?
  • What is the difference between steel and cast iron regarding their composition?
  • Why is carbon used as an alloying element for steel?
  • Why do further phase transformations take place in the already solidified state in steels?
  • In which lattice structure does steel crystallize first?
  • Which lattice structure does steel (usually) have at room temperature?
  • What is the steel part in the phase diagram?
  • How does the carbon content influence the solidification range of steels?
  • What is austenite and ferrite?
  • How does the carbon content affect the transformation of \(\gamma\)-iron into \(\alpha\)-iron?
  • Which microstructural changes occur in the stable or metastable system during the \(\gamma\)-\(\alpha\)-transformation?
  • What promotes the respective systems?
  • Which system is relevant for steel and which for cast iron?
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Phase transformations in solidified state (metastable system)

This article provides answers to the following questions, among others:

  • What is the carbon content of a eutectoid steel?
  • Why is virtually no carbon soluble in ferrite?
  • What phases does pearlite consist of and at what temperature does it form?
  • What is the structure of pearlite under the microscope?
  • What is the difference in the name between eutectic and eutectoid?
  • Why does the solubility of carbon in austenite decrease with decreasing temperature?
  • What is the maximum percentage of carbon that can be dissolved in austenite and at what temperature?
  • What is an undersaturated, supersaturated and saturated state?
  • How is the insoluble carbon precipitated from austenite?
  • What does the microstructure of a hypereutectoid steel look like?
  • How is carbon precipitated in hypoeutectoid steels during \(\gamma\)-\(\alpha\)-transformation?
  • What does the microstructure of a hypoeutectoid steel look like?
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Cast iron

This article provides answers to the following questions, among others:

  • What is the difference in microstructure between steels and cast iron?
  • For which manufacturing processes are steels particularly suitable compared to cast iron?
  • What is the difference between the phase diagram of the stable and the metastable system?
  • What is white and grey cast iron?
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