Effect of cooling and CMT mode process on additive manufacturing

ABSTRACT

Cold metal transfer (CMT) additive manufacturing (AM) is widely used for its efficiency and low cost, in order to improve the efficiency the manufacturing,this study carried out CMT arc modes and interlayer cooling time depositions, and researched deposition stability, roughness, microstructure, and properties. Moreover, as the tensile anisotropy was a significant characteristic of arc AM, this study conducted tensile fracture metallographic test, and revealed the tensile anisotropic mechanism. The results showed that CMT mode was the most stable process, and CMT Plus Pulse (CMT+P) mode with an alternating of CMT and pulse processes had a finer grain and bigger hardness. Although an interlayer cooling time refined the grain size, it also increased the deposited time and roughness. Then, deposition efficiency of CMT+P continuous deposition was up to 87.9%, which realized the forming efficiency. The tensile fracture metallographic test indicated the deformed columnar grains were widened by horizontal stretching, and then the fracture occurred at the grain boundaries. However, no obvious grain deformation occurred under the vertical tension, and the columnar grain boundaries were the weak link of tensile fatigue. Thus, horizontal tensile strength with more grain boundaries was smaller than the vertical one.

KEYWORDS:

• Cold
• metal
• transfer
• additive
• manufacturing
• efficiency
• metallographic
• anisotropy

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the [National Natural Science Foundation of China] under Grant [numbers 51875213 and 51805099]; [Guangzhou Science and Technology Plan Project] under Grant [number 201805010001]; [Project of Educational Commission of Guangdong Province of China] under Grant [number 2020ZDZX2019]; and [Science and Technology Planning Projects of Guangzhou], under Grant [number 201905010007].