Functionally graded carbon steel produced by WAAM from a single wire

This paper investigates the fabrication of functionally graded carbon steel components using Wire Arc Additive Manufacturing (WAAM) with a single feedstock wire (ER100S-G). By systematically varying the deposition parameters, two distinct thermal regimes were established: High Heat Input (HHI) and Low Heat Input (LHI). This induced specific material properties within a single wall, where the HHI regions displayed a coarser grain structure characterized by lower hardness and mechanical strength but higher ductility, whereas the LHI regions exhibited refined microstructure with superior hardness and strength. Uniaxial tensile tests on various graded configurations demonstrated that the mechanical performance and failure location can be controlled by the spatial arrangement of the HHI and LHI layers. A finite element model was developed and validated against experimental results, confirming the potential of this approach to design components with tailored performance. The results show that single-wire functional grading is a viable method for optimizing structural steel components without the complexity of multi-material deposition.