A rotor includes a first rotor segment having a first outer surface and a second rotor segment having a second outer surface. A mechanical joint is between the first and second rotor segments, and a cavity is radially outward of the mechanical joint and beneath the first and second outer surfaces. A weld bead is between the first and second outer surfaces. A method for manufacturing a rotor includes machining a first rotor segment having a first concentric axis of rotation and machining a second rotor segment having a second concentric axis of rotation. The method further includes aligning the first rotor segment to the second rotor segment radially using a mechanical joint and applying a weld bead over a portion of the first and second rotor segments to connect the first rotor segment to the second rotor segment.