Graphite containing free-cutting steel - which is lead-free and has good hot working properties

摘要

The free-cutting steel has the compn. 0.20-0.90% C, which at least in part is in the form of graphite, 1.0-2.3% Si, 0.1-0.7% Mn, max. 0.015% S, 0.015-0.1% Al, and/or Ti, and 0.01-0.2% rare earth elements, balance Fe and usual impurities. The steel contains a graphite No. of at least 50 per mm2. A pref. compsn. is 0.20-0.90% C, in part as graphite, 1.0-2.3% Si, 0.1-0.7% Mn, max. 0.01% S, 0.015-0.1% Al and/or Ti, 0.01-0.2% rare earth elements 0.0005-0.030% Ca. balance Fe, and graphite No. 500-4000 per mm2. The steel has improved tensile strength, alongation and machining life.