Abstract
Introduction: In the past three decades, additive manufacturing (AM), also known as 3D printing, has emerged as a promising technology, which allows the manufacture of complex parts by adding material layer upon layer. In comparison, with other metal-based AM technologies, gas metal arc welding-based additive manufacturing (GMAW-based AM) presents a high deposition rate and has the potential for producing medium and large metal components. To validate the technological performance of such a manufacturing process, the internal quality of manufactured parts needs to be analyzed, particularly in the cases of manufacturing the parts working in a critical load-bearing condition. Therefore, this paper aims at investigating the internal quality (i.e., and mechanical properties) of components manufactured by the GMAW-based AM technology.
 Method: A gas metal arc welding robot was used to build a thin-walled component made of mild steel on a low-carbon substrate according to the AM principle. Thereafter, the specimens for observing and mechanical properties were extracted from the built thin-walled component. The of the specimen were observed by an optical microscope; the hardness was measured by a digital tester, and the tensile tests were carried out on a tensile test machine.
 Results: The results show that the GMAW-based AM-built thin-walled components possess an adequate that varies from the top to the bottom of the built component: structures with primary dendrites in the upper zone; granular structure of with small regions of at grain boundaries in the middle zone, and grains of in the lower zone. The hardness (ranged between 164±3.46 HV to 192±3.81 HV), yield strength (YS offset of 0.2% ranged from 340±2 to 349.67±1.53 ), and ultimate tensile strength (UTS ranged from 429±1 to 477±2 ) of the GMAW-based AM-built components were comparable to those of wrought mild steel.
 Conclusions: The results obtained in this study demonstrate that the GMAW-based AM-built components possess adequate and good mechanical properties for real applications. This allows us to confirm the feasibility of using a conventional gas metal arc welding robot for additive manufacturing or repairing/re-manufacturing of metal components.
Highlights
In the past three decades, additive manufacturing (AM), known as 3D printing, has emerged as a promising technology, which allows the manufacture of complex parts by adding material layer upon layer
The results show that the gas metal arc welding (GMAW)-based AMbuilt thin-walled components possess an adequate microstructure that varies from the top to the bottom of the built component: lamellar structures with primary austenite dendrites in the upper zone; granular structure of ferrites with small regions of pearlites at grain boundaries in the middle zone, and equiaxed grains of ferrites in the lower zone
The upper zone (Figure 3a) presents lamellar structures with primary austenite dendrites that distribute along the cooling direction - perpendicular to the substrate
Summary
In the past three decades, additive manufacturing (AM), known as 3D printing, has emerged as a promising technology, which allows the manufacture of complex parts by adding material layer upon layer. With other metal-based AM technologies, gas metal arc welding-based additive manufacturing (GMAW-based AM) presents a high deposition rate and has the potential for producing medium and large metal components. Conclusions: The results obtained in this study demonstrate that the GMAW-based AM-built components possess adequate microstructure and good mechanical properties for real applications. This allows us to confirm the feasibility of using a conventional gas metal arc welding robot for additive manufacturing or repairing/re-manufacturing of metal components. In comparison with laser-based and electron beam-based AM systems, welding-based additive manufacturing - called wire arc additive manufacturing (WAAM) has demonstrated as a prospective solution for the manufacture of medium and large-dimensional metal parts 6. The arc heat source used in a WAAM system can be gas metal arc welding (GMAW), gas tung-
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
