Punch for use in a pellet press
US5024559A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 28, 1990 |
| Grant date | Jun 18, 1991 |
| Priority date | — |
| Expiry date | Feb 28, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C29/08
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
An apparatus for forming a pellet is disclosed that includes at least one punch that is reciprocably movable through an opening in a die for compressing a granular material, such as uranium dioxide, into a pellet such as the fuel pellets used in the fuel assemblies that generate power in nuclear reactors. The punch is advantageously formed from an alloy consisting essentially of tungsten carbide having a grain size of less than one micron which is embedded in a matrix of cobalt which constitutes between 16.5 and 17.5% by weight of the alloy. The alloy is preferably hot isostatically pressed to achieve zero porosity and a density of approximately 14.0 gm/cc.sup.3. Additionally, essentially pure ingredients are preferably used to avoid interfaces in the resulting alloy which could provide situs for chipping. The resulting alloy has a Rockwell scale A hardness of 89.0, and results in a punch which, even when chamfered around its edges, is capable of producing a large number of uranium dioxide fuel pellets without chipping.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.