Patent ID: 8850705

Claim:
A process for producing exhaust gas manifolds, which have a flange for fastening to a cylinder head of an internal combustion engine, manifold pipes fastened at a first end to the cylinder head for leading off exhaust gases flowing from the cylinder head, and a pipe connector, wherein the pipe connector has non-circular openings for connecting to a second end of each manifold pipe, the process comprising: reinforcing the non-circular openings of the pipe connector, a number of the reinforced non-circular openings formed in the pipe connector corresponding to a number of manifold pipes; inserting the second ends of the manifold pipes into the reinforced non-circular openings of the pipe connector; and expanding the second ends of the manifold pipes that are introduced into the reinforced non-circular openings of the pipe connector with the aid of an expansion tool, thereby undergoing plastic deformation such that each of the second ends of the manifold pipes are fitted completely gas-tight into the reinforced non-circular openings of the pipe connector.