A decanter centrifuge for separating a supplied material in a light phase and a heavy phase comprises an elongate bowl arranged for rotation about its longitudinal axis, the bowl has a separation chamber with a circumferential wall, a screw conveyor (3) being provided in the separation chamber and being coaxial with the bowl, the screw conveyor comprises a conveyor hub (14). The conveyor hub comprises a longitudinal tubular steel body part (18) and a helical steel conveyor flight (15) attached to the tubular steel body part. The conveyor hub further comprises an inner longitudinal body extending coaxially relative the longitudinal tubular steel body part. The inner longitudinal body (19) is extended through at least a part of the tubular steel body and is made of a first material, such as carbon fibre reinforced epoxy, whose specific modulus is larger than specific modulus of the steel material of the tubular steel body part.