Process for lost foam casting of metal parts
US5058653A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 10, 1990 |
| Grant date | Oct 22, 1991 |
| Priority date | — |
| Expiry date | Jul 10, 2010 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB22D27/13
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An improvement in the lost foam casting process in which a foam pattern of a part to be cast is immersed in a dry sand mold and the mold is filled with molten metal in order to burn the pattern. According to the improvement, after filling but before the solidified fraction of metal exceeds 40% by weight, an isostatic gas pressure which increases at a predetermined and substantially constant rate to a predetermined maximum value is applied to the mold and maintained at the maximum value until solidification occurs. The rate of increase of pressure is determined as a function of the granulometry of the sand and depth of immersion of the pattern, to cause due to a temporary lag in pressure transmittal through the sand, a rapid and temporary overpressure of the molten metal relative to the sand at the sand/metal interface. The overpressure reaches a maximum value of 0.001 to 0.030 MPa at the beginning of the pressure application and declines as the applied pressure further increases. The invention is especially useful in the production of cast aluminum alloy parts having an improved level of compactness and a surface which is free from blowholes and carbon inclusions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.