The invention relates to a metallic heat exchange core (1) having ribs (2) which run round on the outside of the core in an annular or helical fashion or extend in the axial direction and serve to condense vapours from pure substances or mixtures on the outside of the core. In order to improve the condensation execution by film thinning, it is proposed according to the invention that the ribs (2) extend continuously at a uniform rib height (H), the rib flanks (4) being structured by means of depressions (5) spaced from one another (Fig. 2). <IMAGE>
