Free Cutting Steel also called Free Machining Steels are steels which are easy to machine. The machinability of the material is increased as the chips are broken in small pieces when machined thus avoiding their entanglement in the machinery. This enables automatic run of the equipment without human interaction. Free cutting steels with lead also allow for higher machining rates. As a thumb rule, free cutting steel normally costs 20% to 30% more than the standard steel. However this is made up by increased machining speeds, larger cuts, and longer tool life.

In turning, milling and drilling operations commonly known as machining operations, deformation/welding of the tool/work piece interface occurs rather than chip formation. During the machining operations surface finish is impaired, cutting temperature increased and tool life reduced significantly. A large ‘built-up edge’ is formed on the tool tip at very low sulfur contents. This requires frequent dressing or changing of tools, reduced productivity and higher costs.