How does manganese remove sulfur from steel?

Manganese acts as a desulfurizer in steelmaking because it possesses a greater chemical affinity for sulfur than iron does. During the process, manganese reacts with sulfur to convert low-melting iron sulfide into high-melting manganese sulfide particles.12

By forming these stable, high-melting compounds, manganese effectively removes sulfur from the crystalline grain boundaries of the metal. This is critical because sulfur located at these grain boundaries can cause "hot shortness," a condition that makes steel unable to withstand the stresses of hot working, such as forging or rolling. Without the addition of manganese, steel would typically break apart during these high-temperature manufacturing processes.21