Surface heat treatment of piston rings
US6485027B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 29, 1999 |
| Grant date | Nov 26, 2002 |
| Priority date | — |
| Expiry date | Jan 29, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49297
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A piston ring for use in a piston of an internal combustion engine comprises a base material of a first hardness formed into a ring, and a secondary material of a second hardness formed by selective and superficial heat treatment of an outer portion of the base material. At least one outer surface of the ring is selectively and superficially heat treated in one of a variety of ways to form an austenitic metal layer about 100 &mgr;m thick on the surface of the ring. The ring is then rapidly cooled in an appropriate environment, resulting in the transformation of the austenitic compound into a martensitic compound adjacent the base material at the point of heat treatment. Preferably, the martensitic metal has a hardness range of 800 to 1000 HV (Vickers Hardness scale) measured at a load of 100 grams.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.