The invention relates to a control valve having a valve seat and a valve disk (1), which can be moved from a closed position, in which the valve disk (1) rests on the valve seat and the relief valve is closed, into a through-flow position, in which the relief valve is open, wherein the valve disk (1) comprises a valve disk surface (2) having a peripheral surface rim (4) and a normal which is perpendicular to the valve disk surface (2), runs through the center of gravity of the latter and defines a longitudinal axis L. A brim is arranged on the surface rim (4), wherein said brim has a first part (6) which projects beyond the valve disk surface (2) in the axial direction with respect to the longitudinal axis L and has a second part (8) which adjoins the first part (6) and comprises a section that is radial with respect to the longitudinal axis L.