Comparison of different process variations in gas metal arc welding for wire arc additive manufacture

Abstract

Additive manufacturing is becoming more and more present in the industry due to its ability to 3D print metal parts with complex geometries that are very difficult and sometimes impossible to achieve with machining. The Gas Metal Arc Welding (GMAW) process stands out in the AM field because it combines high productivity with low operating costs. However, the heat input applied by the GMAW process is one of the biggest challenges to the AM process, affecting the mechanical properties of the manufactured part, causing cracks and distortion. Therefore, different short circuit process variations from different power sources are being tested to analyze their impact on the heat input on the AM process. These processes are used to produce a weld bead with defined geometry. Comparison is made with macrographs to observe penetration and the theoretical heat input is calculated. Three processes between those tested are used to develop an additive manufacturing of a wall assisted by a thermal camera. The temperature distribution during the AM process is presented and the mechanical characteristics of the walls are compared with geometry, hardness test, macro and micrographs. The results showed that the improvement of the standard short circuit by power control and retractable wire feed technique could lead to a reduction of 20% of the heat input and up to 50% of the penetration reduction. The comparison of the processes applied to an AM process showed differences in the geometry produced, with the retractable wire feed processes producing a thinner and continuous wall. The hot process could not maintain the controlled wall thickness and produced a deformed body. Hardness tests and micrographs showed no significant differences between the processes tested.