In order to produce a wall profile on an inside of a plastically deformable hollow body wall of a hollow body, a forming mandrel is arranged in the interior of a cavity of the hollow body so that the forming mandrel extends at the level of a first longitudinal portion of the hollow body wall with a mandrel portion having an enlarged cross-section, which has a forming mandrel profile portion and a cross-sectional oversize compared to a mandrel portion having a reduced cross-section, which extends at the level of a second longitudinal portion of the hollow body wall and has a further forming mandrel profile portion. A forming die is moved with a forming movement relative to the hollow body wall and relative to the mandrel portion with an enlarged cross-section and relative to the mandrel portion with a reduced cross-section of the forming mandrel.

In order to produce a wall profile on an inside of a plastically deformable hollow body wall of a hollow body, a forming mandrel is arranged in the interior of a cavity of the hollow body so that the forming mandrel extends at the level of a first longitudinal portion of the hollow body wall with a mandrel portion having an enlarged cross-section, which has a forming mandrel profile portion and a cross-sectional oversize compared to a mandrel portion having a reduced cross-section, which extends at the level of a second longitudinal portion of the hollow body wall and has a further forming mandrel profile portion. A forming die is moved with a forming movement relative to the hollow body wall and relative to the mandrel portion with an enlarged cross-section and relative to the mandrel portion with a reduced cross-section of the forming mandrel.