Annealing processes

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

  • What are the objectives of annealing processes, such as normalizing, soft annealing, coarse grain annealing, recrystallisation annealing, diffusion annealing, solution annealing and stress-relief annealing?
  • In which temperature ranges are the annealing processes carried out?
  • Why is an improvement in machinability also achieved with soft annealing?
  • How can the generally poorer properties of a coarse-grained microstructure be subsequently removed?
  • What is the significance of recrystallisation annealing for transformation-free steels?
  • What is hot forming or cold forming?
  • Why is diffusion annealing relatively cost-intensive?
  • Why does the workpiece have to be cooled slowly after stress relief annealing?
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Quenching and tempering

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

  • What is the aim of quenching and tempering compared to hardening?
  • In which three process steps can quenching and tempering be divided?
  • Why is quenching and tempering not counted as an annealing process?
  • Why must the steel be kept at a specific temperature for a certain time during austenitizing?
  • What microstructural changes occur during quenching?
  • What are the characteristics of the martensitic microstructure?
  • What properties must steels have for quenching and tempering?
  • What is bainite?
  • What is a surface-hardening steel?
  • Why should high-alloy steels not be quenched as much as unalloyed steels?
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Surface hardening (case-hardening)

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

  • What are the characteristics of surface-hardened workpieces?
  • How is the depth of the hardening layer controlled during flame hardening?
  • What are the advantages of induction hardening compared to flame hardening?
  • Why does laser hardening not require quenching with water?
  • For which steels is case hardening suitable and what are the mechanical properties of case hardened components?
  • What are single-quench hardening, double-quench hardening and direct hardening?
  • For which steels is single or double quench hardening used in comparison to direct hardening?
  • How does nitriding differ from all other surface hardening methods?
  • What is the primary objective of nitriding?
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