Patent ID: 6579385
Filing Date: 2003-06-17
Classification: C22C

Abstract:
A free machining steel for use in machine structures in which sulfide inclusions are present, wherein Mg is contained by from 0.0005 to 0.02 mass % and a distribution index F1 for the sulfide inclusion particles defined by the following equation (1) is from 0.4 to 0.65:F1=X1/(A/n)Â½â€ƒâ€ƒ(1), whereX1: represents an average value (&mgr;m) obtained by actually measuring the distance between each sulfide inclusion particle in an observed visual field and another particle nearest thereto for all of particles present in the observed visual fields, measuring the distance for five visual fields and averaging them, where A: represents an observed area (mm2), and n: represents the number of sulfide inclusions observed within the observed area.