Abstract:
A casting for conducting high temperature gases, such as an internal combustion engine cylinder head (20) having to pass combustion exhaust gases therethrough, and a method of manufacturing the same wherein the casting includes a main body portion (20) and a high strength steel exhaust port liner (26) with a heat insulating chamber (62) therebetween filled with hollow ceramic particles. The liner (26) is cast in place thereby affixing the liner to the casting by means of diffusion bonding (52, 54) during the casting of the cast article. The liner (26) and a low heat conductivity insulation blanket of hollow ceramic particles surrounding the liner (26) and an annular steel ring (58), which serves as a thermally expanding seal between the casting and liner which also allows axial displacement between the casting and liner, are all provided as a unitary mold core prior to the casting of the cast article.