Patent ID: 6527879
Filing Date: 2003-03-04
Classification: F16J

Abstract:
An elongate piston ring material with self-lubrication adapted to be suitable for producing a piston ring for an internal combustion engine, said piston ring material comprising a steel consisting essentially, by mass, of not less than 0.3% but less than 0.8% carbon, 0.1 to 3.0% silicon, 0.1 to 3.0% manganese, 0.03 to 0.3% sulfur, 0.3 to 6.0% chromium, 0 to 3.0% copper, and the balance iron, said piston ring material including sulfide inclusions each having aspect ratio, that is, ratio of maximum size to minimum size, not less than 3 when observed in longitudinal structure of said material, said sulfide inclusions in said longitudinal structure being oriented so that an intersecting angle made between an imaginary, straight line passing said maximum size of any one of said sulfide inclusions and another imaginary, straight line passing said maximum size of another of said sulfide inclusions is not more than 30 degrees.