An additive manufacturing machine includes a heated gas circulation system for regulating the temperature of additive powder throughout an annular powder bed and parts formed therein. The additive manufacturing machine includes an annular build platform defining a plurality of perforations and a heated gas supply that provides a flow of heated air through the plurality of perforations and the powder bed. The additive manufacturing machine further includes a plurality of fairings for guiding the flow of heated gas to temperature sensitive regions to minimize temperature gradients within the powder bed which might otherwise result in distortion, thermal stresses, or cracking in the finished part.