Explanation

steel with chemical composition lower than eutectoid composition. The non alloy is a steel with carbon content less than 0.77%. The room temperature equilibrium structure is pearlite plus proeutectoid ferrite. The ferrite content decreases with the increase of carbon content, while the pearlite content increases with the increase of carbon content in steel. Most engineering structural steel belongs to hypoeutectoid steel, which can directly produce various engineering components without heat treatment; Most mechanical structural steel also belongs to hypoeutectoid steel, which is used to make various mechanical parts and needs to be used after heat treatment (quenching and tempering, normalizing, surface hardening, etc.).

Classification