Abstracts
Due to its varied range of applications, the short circuit GMAW process is highly used in the industry. Among the welding processes available in the market, this one stands out for delivering low cost and high productivity, being commonly used in naval field as root pass and also in additive manufacture for turbines production. Nevertheless, the heat input applied for this process is one of the main challenges when regarding applications where sensitive materials are used and precision is required, since high temperatures imply residual stress and possible structural damages. Therefore, the short circuiting metal transfer technologies developed by different companies are tested to study their methods to control the temperature in the welding process. This knowledge may help to understand the influences of the parameters and, then, to parameterize the process and select a technology among so many available in the market. The processes divided in standard, electrically controlled and retractable wire feed short circuit are used to produce a weld bead with similar geometry and have their performance analyzed developing the same task. As one of the most recent applications of modified short circuit GMAW, an exploratory additive manufacturing test is developed with three different processes to compare their methods and performances. The electrical parameters of each process are measured and the theoretical heat input is calculated and compared. A macrograph of the result weld beads is made to analyze the penetration and its relation with the deposition. It was observed throughout the heat input and penetration areas comparison that the theoretical heat input does not describe the physical performance of the processes. Some samples showed higher theoretical heat input and smaller penetration than others. Therefore, the physical performance can be better predicted by observing the process electric waveform, where drop detachment frequency, power peak and low current intervals are very influential. The standard short circuit processes showed the highest penetrations, followed by the electrical controlled processes. The retractable wire feed processes showed the lowest penetration values. In the theoretical heat input measured was not possible to observe significant advantages between the electrical controlled and standard processes, with exception for the ECP 2 technology. The retractable wire feed processes had the best results in the metrics, showing the lowest theoretical heat input and penetration. The preliminary AM procedure showed a big range of geometry changes, with the retractable wire feed processes controlling better the heat input, leading to a more continuous part.
Referência:
Wiggers, J. F.; Silva, R. H. G.. Comparative study of heat input in conventional and advanced short circuit GMAW variants. SOBENA 2024 - 30º Congresso Internacional de Transporte Aquaviário, Construção Naval e Offshore. Rio de Janeiro/RJ, 22-24 de outubro de 2024