Titanium engine valve and method of making
US4729546A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 27, 1987 |
| Grant date | Mar 8, 1988 |
| Priority date | — |
| Expiry date | Jan 27, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22F1/183
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method is disclosed for making a dual microstructure titanium based engine valve, wherein a first zone of the valve contains essentially a mixture of fine, equiaxed alpha and transformed beta crystalline grains which exhibit high tensile strength and high fatigue resistance, and a second zone of the valve which contains essentially a colony type microstructure exhibiting resistance to high temperature creep. The method comprises: (a) preparing a valve stock of forgeable mixed phase alpha/beta titanium based material; (b) hot working said first zone at a temperature below the beta transus temperature, (c) forging said second zone and, either simultaneously with said forging or subsequent thereto, heat treating said second zone at a temperature above (e.g., 25.degree.-200.degree. F. above) the beta transus temperature for a period of time to achieve beta processing followed by cooling to 1400.degree. F. at a rate of 0.1.degree.-10.0.degree. F./second; and (d) heat treating, immediately subsequent to either step (b) or step (c), at least the first zone at a temperature below the beta transus temperature (e.g., 25.degree.-200.degree. F. below) for a period of time to achieve alpha/be…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.