PURPOSE: To prolong the service life of a metallic frame by forming a crossing step part between the forming surface at the outer peripheral part of a tube end and the forming surface of a flange with a metallic material having high thermal conductivity or low coefficient of thermal expansion to a cast steel body of the metallic body.

CONSTITUTION: Centrifugal force casting is executed to a flangeshape tube 21 extending the flange from the outer peripheral part of the tube end by the metallic frame 1 for centrifugal force casting. Then the crossing step part between the forming surface 4 at the outer peripheral part of the tube end and the forming surface 3 of the flange formed on the inner peripheral surface at the end part of the metallic frame body 2 is constituted with a ring material 7. This ring material 7 is formed with the metallic material having high thermal conductivity or low coefficient of thermal expansion to the cast steel material forming the metallic frame body 2. As the ring material, e.g. copper, titanium or stainless steel is used. By this method, the heat expansion quantity is restrained and the development of crack in the metallic frame can be prevented.