Abstract: The thermal differential mouldless forging of the AISI 1045 steel cylindrical rod subjected to ring heat sources,as an example,is simulated by using coupled thermal-viscoplastic FEM.The results reveal that it is feasible to use the thermal differential mouldless forging as a new near net forming process.Obtaining and controlling appropriate nonhomogeneous temperature distributions within met al billet is key for this forming process.The suitable combination of the heating and cooling rings can produce such temperature distributions.The met al flow mode is basically determined by temperature distributions prior to deformation under fast deformation operation and is affected very slightly by continuously in-situ heating during deformation.But the met al flow mode is affected by both the temperature distributions prior to deformation and the continuously in-situ heating during deformation under slow deformation operation.