Patent ID: 6783728
Filing Date: 2004-08-31
Classification: C22C

Abstract:
A free-cutting steel for machine structural use consisting essentially of, by weight %, C: 0.05-0.8%, Si: 0.01-2.5%, Mn: 0.1-3.5%, S: 0.01-0.2%, Al: 0.001-0.019%, Ca: 0.0005-0.02% and O: 0.0005-0.01%, the balance being Fe and inevitable impurities, and is characterized in that the area in microscopic field occupied by the sulfide inclusions containing Ca of 1.0% or more neighboring to oxide inclusions containing CaO of 8-62% is 2.0Ã—10âˆ’4 mm2 or more per 3.5 mm2.