Free-cutting structural steel for machines

摘要

The present invention relates to a free-cutting structural steel for machines characterized by containing a range of 30-100 g/steel ton of oxide inclusions mainly composed of SiO2 40-60%, CaO 13-30% and Al2O3 25-40%, the balance being less than 20% of other oxides and calcium 0.0002-0.0010%, and at least one of the following elements; lead 0.03-0.30% and sulfur 0.035-0.10%.