Abstract: Composite material 19 comprising outer member 17 having ring form section and inner member 18 mounted into said outer member so as to form a unitary construction, wherein inner surface 24 of said outer member 17 and outer surface 22 of said inner member 18 are at least partially opposed to each other through a gap .delta. and wherein said members 17,18 are joined together by means of anaerobic adhesives filling said gap .delta..

Abstract: An oil seal of the type having a metallic reinforcement rig whose outer peripheral portion is oil-tightly fitted into a housing, characterized in that after the formation of fabrication of said metallic reinforcement ring, the latter is subjected to a nitriding hardening process so that its durability of a raw material of said metallic reinforcement ring; and a seal lip of formed over the inner peripheral edge portion of an annular flange portion of said metallic reinforcement ring.

Abstract: A method for molding a cover on a metal core by preforming cover segments and molding the latter to size with the core interposed therebetween. When molded, the preformed segments are gradually deformed and uniformly compacted to a high density particularly in regions in direct contact with the wall surfaces of the mold, with no inclusion of cracks, pinholes or other structural defects therein. The product molded in this manner exhibits a very high corrosion-resisting characteristic with no machining operation conventionally required thereon, particularly when molded of tetrafluoroethylene resin powder.