International Journal Of 3D Printing And Additive Manufacturing

Fabrication of metal parts by wire and Arc Additive Manufacturing (WAAM) has received an increased interest in recent years, as it allows high design flexibility and reduction of material wastage compared to other traditional manufacturing routes. This article compares the effect of heat input on metallurgical characteristics of wire arc additive manufactured low carbon steel cylindrical components fabricated by Gas Metal Arc Welding (GMAW) and Cold Metal Transferred Arc Welding (CMTAW) processes. Firstly, the influence of heat input on the grain size was analyzed. Subsequently, the effect of heat input on the metallurgical characteristics of the cylindrical components was studied along the building direction. The microstructure of the built cylindrical-walled component varies from the top to the bottom regions and can be distinguished into two regions: lamellar structures (widmanstatten ferrite and grain boundary ferrite) in the top regions; and equated grains of fully ferrite in the bottom region in GMAW. In the CMT-WAAM cylindrical component samples have been noted two different regions: the bottom region characterized by a ferritic structure with thin strips of pearlite and the top region characterized by a lamellar structure typically bainite with acicular ferrite.

Keywords: Wire arc additive manufacturing, gas metal arc welding, cold metal transfer arc welding, low carbon steel and microstructural characteristics.