A turbine housing of an exhaust gas turbocharger includes an outer casing and a rotor casing which is arranged in the outer casing and includes a tubular neck for engagement in an exhaust pipe to conduct exhaust gas from the neck in a direction of an exhaust flange. The exhaust pipe is hereby coupled to the rotor casing for relative movement there between. A sealing ring is arranged between the neck and the exhaust pipe, wherein the neck has one end provided with at least one outwardly directed projection defined by an outer diameter which is greater than an inner diameter of the sealing ring. Fabrication of the turbine housing is realized by pushing the sealing ring over the neck, and inserting an expanding mandrel into the neck to widen the neck.