Study of a hardfacing flux-cored wire for arc directed energy deposition applications

This paper investigates the feasibility of producing hard structures capable of wear resistance by depositing a hardfacing flux-cored wire while using arc directed energy deposition (DED-Arc) as process. The present paper discloses the compatibility of a metal hardfacing flux-cored wire with this technology by deposition of single walls and block fabrication. The deposition of walls and blocks was made using different parameters and deposition strategies, in order to avoid solidification cracking associated with the precipitation of chromium carbides. Macro and microstructural analyses, as well as hardness tests, were carried out to validate the use of this wire with DED-Arc. The use of a grinder for slag removal was also investigated. Withal, the deposition of a 40-layer wall and blocks indicated that a hardfacing flux-cored wire can be used to produce a near net shape part by additive manufacturing. Additionally, gradient properties of additively manufactured metal parts can be achieved by depositing layers of materials with different characteristics and, with DED-Arc, this can be done through the use of different types of metal wire. Thus, studies on the possibility of constructing a bi-metallic part, by DED-Arc, using a low carbon steel (ER70S-6) and the same hardfacing-cored wire were developed, focusing on crack minimization procedures, such as the application of pre-heating. Assessment of metallurgical transformations and mechanical properties were investigated to assure that the material properties were kept. A final multi-metal part was produced with DED-Arc.