Method of making a cylinder head or other article with cast in-situ ceramic tubes
US5251683A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 11, 1991 |
| Grant date | Oct 12, 1993 |
| Priority date | — |
| Expiry date | Mar 11, 2011 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02F1/24
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method is disclosed for making an article, such as a cylinder head, having one or more hollow ceramic tubes, such as ceramic exhaust port liners, cast in-situ therein with reduced cracking or breakage of the ceramic tube from tensile and compressive stresses exerted on the ceramic tube during the casting process. The method involves forming a removable core in the ceramic tube of a core material having a thermal expansion coefficient not exceeding about 10 times that of the ceramic tube to minimize crack-causing differential thermal expansion-induced tensile stresses on the ceramic tube when molten metal is cast therearound, casting the molten metal about the cored ceramic tube in a mold cavity, stress relieving the cast article at an elevated temperature before the cast article cools to a lower temperature at which crack-causing differential thermal contraction-induced compressive stresses are exerted on the cast in-situ ceramic tube, and removing the core from the cast article.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.