Mechanical Properties of Steel Printed on Ceramics

Abstract

Construction industry is about to embrace 3D printing as a viable technology for fabricating structures that are not physically or commercially impractical. These include curved components that could be embedded in buildings. On the other hand, whole house building by 3D printing has been attempted around the world using giant concrete printers. The main question is how to integrate steel rebars in concrete by 3D welding and still maintain the structural integrity and reliability of the conventional rebars. To accomplish the incorporation of rebars in concrete, steel must be welded within concrete. Heat dissipation rates may be different in different directions when the 3D molten weld pool solidifies, especially when the substrate is concrete. This may affect the strength of the material along and across the weld bead. To investigate this effect, it is important to study the mechanical properties of 3D welded steel in the directions of length, thickness and width. Experiments conducted in this study include the 3D welding of steel on concrete tiles by attaching the torch of a MIG welder to a meter-scale 3D printer carriage. The weld beads were then cross sections in directions along the weld bead, across the bead and perpendicular to the ceramic substrate. Dog-bone shaped micro-scale samples were extracted along those direction by CNC machining and EDM milling. The specimens were then mounted on the grippers of a hybrid micro-tester and tensile tests were carried out. The results of the tests are reported, and the implications of the findings in terms of the feasibility of 3D printing of steel reinforced concrete are discussed.