Which type of steel typically undergoes an increased risk of brittleness during the annealing process?

High carbon steel is particularly susceptible to brittleness during the annealing process due to its elevated carbon content. When high carbon steels are subjected to annealing, the heat treatment can lead to the formation of hard, brittle microstructures if not carried out correctly. In these steels, the carbon content can contribute to the distribution of carbon phases, which can result in less ductility if the material is cooled too quickly after heating or not heated to the appropriate temperature.

In contrast, low carbon steels typically have a more ductile nature and are less prone to developing brittleness during annealing. Medium carbon steels can also experience changes during annealing, but their composition lies between low and high carbon steels, making them relatively more resilient than high carbon steels.

Moreover, while all carbon steels may face some risk during the annealing process, it is the high carbon variety that stands out due to its specific behavior in relation to changes in microstructure and mechanical properties when subjected to heat treatment. This understanding of the material properties is crucial for engineers in selecting the appropriate steel type for applications that require good toughness and ductility.