Abstract: A catalytic converter for an automotive exhaust system or the like comprises a catalyst substrate disposed within a seamless metal housing preferably formed by a spin-forming process. The housing includes a midsection surrounding a catalyst substrate and an end section that extends from the midsection and defines an opening, which may be either an inlet or an outlet for the converter. An inner heat shield is affixed to the housing end section at the opening and includes a frustoconical section that is disposed about the substrate such that the substrate end is received in the frustoconical section. The frustoconical section is spaced apart from the first housing end section to insulate the housing end section from the heat of the exhaust gases and thereby reduces the temperature of the metal housing.

Abstract: A method is provided for forming a catalytic converter that includes a catalyst substrate having a noncircular circumference and surrounded by a metal housing. The catalyst substrate is initially measured to determine the radial dimension of the substrate circumference relative to a central axis. The substrate is wrapped in a compressible mat and arranged within a metal tube. The arrangement is subjected to a spin-forming process that forms the metal tube about the catalyst substrate. The spin-forming process includes rotating the metal tube about the substrate axis, while concurrently urging a metal-forming tool against the metal tube. The metal-forming tool is programmed to follow a metal-forming path corresponding to the substrate circumference plus a predetermined radial distance. In this manner, a metal housing is formed having a noncircular circumference corresponding in shape to the catalyst substrate and spaced apart by a uniform insulative layer.

Abstract: A method is provided for forming a catalytic converter comprising a catalyst substrate having a noncircular circumference and a metal housing disposed about the substrate. The catalyst substrate is initially measured to determine the radial dimension of the substrate circumference relative to a central axis. The substrate is wrapped in a compressible mat and arranged within a metal tube. The arrangement is subjected to a spin-forming process that forms the metal tube about the catalyst substrate. The spin-forming process includes rotating the metal tube about the substrate axis, while concurrently urging a metal-forming tool against the metal tube. The metal-forming tool is programmed to follow a metal-forming path corresponding to the substrate circumference plus a predetermined radial distance. In this manner, a metal housing is formed having a noncircular circumference corresponding in shape to the catalyst substrate and spaced apart by a uniform insulative layer.