Process for making exhaust valves
US5257453A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 8, 1992 |
| Grant date | Nov 2, 1993 |
| Priority date | — |
| Expiry date | Jul 8, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49311
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method of making work-hardened poppet exhaust valves for internal combustion engines comprises the steps of: providing 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 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; extruding the coil stock to a poppet valve preform configuration at a speed in the range of 60 to 100 strokes per minute and at a temperature in the range of room temperature to 1,000.degree. F.; and heading the preform at the same speed while maintaining the head of the preform at a temperature in the range of room temperature to 2,200.degree.; the parameters of extrusion providing the work-hardened poppet valve with a stem hardness more than R.sub.c =25.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.