Materials database

Sulfur-manganese free-cutting steel, not intended for heat treatment. Excellent machinability (significantly better than standard carbon steels). Used for high-volume CNC-machined parts: bolts, nuts, pipe joints, bushings, fittings, and other turned components.

Leaded free-cutting steel — the highest machinability rating among carbon steels. Pb+S combination gives excellent chip breaking and surface finish. The standard grade for high-volume automatic lathe parts. Used for screws, nuts, bolts, bushings, pins, and automotive turned parts. ≈ AISI 12L14.

Free-cutting steel with high sulfur for excellent machinability. Very similar to 11SMn30 — historical German designation that is still widely referenced. Lower C variant preferred for some screw machine products. Used for high-volume automatic lathe parts, screws, nuts, pins, and bushings. ≈ AISI 1215.

Leaded free-cutting steel — Pb (0.15-0.35%) + S (0.24-0.33%) for maximum machinability. THE ultimate Automatenstahl: machinability rating ~175% (vs 100% for 11SMn30). Pb acts as chip-breaker and tool lubricant. Used for high-speed automatic screw machine production of screws, nuts, fittings, bushings, and any part where surface finish and cycle time matter most. NOTE: Pb content being phased out under EU ELV/RoHS — replacement grades emerging.