What term describes steel that contains less than 0.8% carbon content?

Steel that contains less than 0.8% carbon content is referred to as hypoeutectoid steel. This classification is important in metallurgy, particularly concerning the microstructural behavior of steel during its cooling and phase transformations.

In the context of the iron-carbon phase diagram, hypoeutectoid steels are those that have carbon content below the eutectoid point (which is at 0.76% carbon). When these steels are cooled, they will primarily transform into a microstructure consisting of a combination of ferrite (which has a lower carbon solubility) and cementite (which is iron carbide). This structure is advantageous because lower carbon content generally results in improved ductility and toughness compared to higher carbon steels.

Understanding the classification of steel types is fundamental in the field of welding and materials engineering, as it directly affects the steel's properties and performance in various applications. This knowledge is essential for making informed decisions about the selection and treatment of materials in welding processes.