The alloying elements can change and personalize properties-their flexibility, strength, formability, and hardenability.As a guideline, alloying elements are added in lower percentages (less than 5%) to increase strength or hardenability, or in larger percentages (over 5%) to achieve special properties, such as corrosion resistance or extreme temperature stability. Manganese, silicon, or aluminium are added during the steelmaking process to remove dissolved oxygen, sulfur and phosphorus from the melt.