Self-lubricating piston ring material for internal combustion engine and piston ring

• US 20020005616A1
• Filed: 06/20/2001
• Published: 01/17/2002
• Est. Priority Date: 06/25/1999
• Status: Active Grant

• Current Assignee: Hitachi Metals (Thailand) Ltd.
• Original Assignee: Hitachi Metals (Thailand) Ltd.
• Inventors: Ohno, Takehiro, Masugata, Yoshiki, Kubota, Kunichika
• Granted Patent: US 6,527,879 B2
• Time in Patent Office: Days
• US Class Current: 277/440
• CPC Class Codes: F16J 9/26 characterised by the use of particular materials

Abstract

There are disclosed a piston ring material and a piston ring both having such superior properties contradictory each other as the sliding property required in a piston ring and the mechanical properties of a steel wire material subjected to a manufacture process. The piston ring material or the piston ring consists essentially, by mass, of not less than 0.3% but less than 0.8% C, 0.1 to 3.0% Si, 0.1 to 3.0% Mn, 0.03 to 0.3% S, 0.3 to 6.0% Cr, preferably 3.0 to 6.0% or 0.3 to 1.0% Cr, 0 to 3.0% Cu, and the balance Fe, and the distribution state of sulfide inclusions with a maximum diameter/minimum size≧3 observed on structure parallel to the outer peripheral surface of the formed piston ring is such that an intersecting angle made between straight lines passing the maximum size of two of the sulfide inclusions is not more than 30 degrees. Further, the area ratio of nonmetallic inclusions occupying the structure is 2.0% or less, or in addition to the above-described composition, at least one selected from the group consisting of 0.01% or less of Ca, 0.5% or less in total of one or more of V, Nb, Ti, and 1.5% or less of Al is contained.

Claims

1. 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.

2. A piston ring material as set forth in claim 1, wherein an area ratio of non-metallic inclusions occupying in the structure is not more than 2%.

5. A piston ring material as set forth in claim 1 or 3, wherein said steel further contains calcium not more than 0.01 mass %.

6. A piston ring material as set forth in claim 1 or 3, wherein said steel further contains 3.0 to 6.0 mass % chromium.

7. A piston ring material as set forth in claim 1 or 3, wherein said steel further contains 0.3 to 1.0 mass % chromium.

8. A piston ring material as set forth in claim 1 or 3, wherein said steel further contains at least one not more than 0.5 mass % in total selected from the group consisting of vanadium, niobium, and titanium.

9. A piston ring material as set forth in claim 1 or 3, wherein said steel further contains aluminum not more than 1.5 mass %.

3. A 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 a structure present in a face parallel to an outer periphery of the piston ring formed of the piston ring material, said sulfide inclusions in said structure being provided with such a distribution state as 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.

4. A piston ring material as set forth in claim 3, wherein an area ratio of non-metallic inclusions occupying in the structure is not more than 2%.

10. A piston ring with self-lubrication for an internal combustion engine, said piston ring 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 including sulfide inclusions each having aspect ratio, that is, ratio of maximum size to minimum size, not less than 3 when observed in a structure present in a face coaxial with an outer periphery of the piston ring, said inclusions in said structure being provided with such a distribution state as 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.

11. A piston ring as set forth in claim 10, wherein an area ratio of non-metallic inclusions occupying in the structure is not more than 2%.

12. A piston ring as set forth in claim 10, wherein said steel further contains calcium not more than 0.01 mass %.

13. A piston ring as set forth in claim 10, wherein said steel further contains 3.0 to 6.0 mass % chromium.

14. A piston ring as set forth in claim 10, wherein said steel further contains 0.3 to 1.0 mass % chromium.

15. A piston ring as set forth in claim 10, wherein said steel further contains at least one not more than 0.5 mass % in total selected from the group consisting of vanadium, niobium, and titanium.

16. A piston ring as set forth in claim 10, wherein said steel further contains aluminum not more than 1.5 mass %.