Abstract: A method for producing a heat transfer member wherein at a first step a work piece (1) is produced comprising a curved base portion (2) with an outer (3) surface, an inner (4) surface, and a number of flanges (5) projecting from the outer surface and in a second step the heat transfer member is formed by straightening out the base portion (2) so that it becomes essentially plane The work piece in the first step is produced so that the distance (a, b) between the outer and the inner surface of the base portion is increasing from its ends towards its central part.