Billet conditioning technique for manufacturing powder metallurgy preforms
US4762679A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 6, 1987 |
| Grant date | Aug 9, 1988 |
| Priority date | — |
| Expiry date | Jul 6, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C2214/08
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process for manufacturing powder metallurgy (P/M) preforms which are conditioned for optimum intrinsic workability is described which comprises steps of heating a quantity of P/M material in a can to a first preselected temperature under vacuum to degas the material, compacting the canned material at a second preselected temperature under pressure to provide a compact of the material; or cold compacting the powder to about 75% density and degassing it at suitable temperature and then vacuum hot pressing the powder at about 0.75 melting point; generating flow stress data as a function of strain rate and temperature on samples of the compact at predetermined strain within predetermined ranges of temperature and strain rate and determining powder dissipation efficiency of the compact and entropy rate ratio within those ranges of temperature and strain rate; selecting values of strain rate and extrusion temperature at which dynamic recrystallization is the dominant metallurgical mechanism characterizing the compact: and extruding the compact in an extrusion can at the selected extrusion temperature and at an extrusion rate corresponding to the selected strain rate using a streamlined…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.