Work hardened poppet exhaust valve
US6635128B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 28, 1994 |
| Grant date | Oct 21, 2003 |
| Priority date | — |
| Expiry date | Nov 28, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49311
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A work-hardened poppet exhaust valve for internal combustion engines is obtained from a solutioned work-hardenable austenitic stainless steel coil or bar stock in which chromium is present in the range of 13%-25% by weight, nickel is present in the range of 4%-16% by weight, manganese is present in the range of 0.25%-8% by weight, copper is present in the range of 0.5%-7% by weight, the interstitial elements carbon plus nitrogen are present in a total amount less than 0.45% by nitrogen are present in a total amount less than 0.45% by weight, and at least one refractory metal selected from the group consisting of molybdenum, niobium, vanadium, tungsten and tantalum is present in the range of 1%-5% by weight. The coil or bar stock is extruded to a poppet valve preform configuration at a temperature in the range of room temperature to 1,000° F., and at a true strain of more than 0.8. The parameters of extrusion provide said work-hardened poppet valve with a stem hardness more than Rc=25.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.