Plasma wire arc additive manufacturing and its influence on high‑carbon steel substrate properties

Steels with a high carbon content are considered to be difficult to weld. High carbon equivalent indicates not only problems when joining such steels but also when using them as substrate in additive manufacturing (AM). In this study, the possibility of manufacturing a high-strength steel structure on a high-carbon steel substrate using plasma wire arc additive manufacturing (PWAAM) is demonstrated. This study deals with the thermal history and its effects on the substrate resulting from a multilayer build-up. In-substrate temperature measurements as well as metallographic and hardness measurement will provide an understanding of the influence of the process on the substrate. Additionally, a local pre-heating concept using penetration depth induction (PDI) is considered. PDI also enables energy rearrangement in which energy is removed from the AM process and introduced directly into the substrate by PDI. These variants of the preheating concept are also being investigated concerning their effects on the substrate and its properties. A comparison of multilayer buildup without and with PDI is intended to show the differences but also the possibilities that can be achieved with the PDI approach. The investigations carried out are intended to create the basis for a quality AM structure on a high-carbon steel substrate as well as optimized properties of the substrate. It is also shown that the transition zone between the substrate and the AM structure is not trivial for such a material combination.