Projeto e caracterização de um protótipo de máquina automatizada para a soldagem TIG de reservatórios de sistemas de aquecimento solar

Abstract

Process automation is an activity with significant potential for economic growth through improvements in repeatability, increased productivity, among other factors. In the Brazilian context, there are numerous companies with a high potential for automation. This work presented the development of the EMBRAPII–UFSCar – Materials project, No. 23112.014919/2020-71, which aimed at the design and construction of an automated machine prototype for TIG (Tungsten Inert Gas) welding of tanks used in solar water heating systems. The prototype validation was carried out through the characterization of the results obtained from the automated welding operation. During the project development, a mechatronic product development strategy was adopted, combining the principles of the VDI 2206 standard with product development models described in national references, such as Back (1983) and Rozenfeld et al. (2006). This strategy was structured into iterative cycles in an attempt to achieve optimal technical solutions. The prototype was designed to have four degrees of freedom, driven by servomotors, with the capability to weld tanks up to 3 m in length and 1 m in diameter. To ensure that the TIG torch maintained the appropriate welding distance, considering the irregularities caused by the radial runout of the tank, an optical sensor integrated with the torch positioning system was employed. The technical validation of the prototype was performed through mechanical and metallographic tests, focusing on the characterization of the quality of welded joints in comparison with manual and automated welding processes. This study not only incorporated data from Coroa (2023) and Cherubim (2024) regarding metallographic analyses of manual and automated welds, but also complemented these results through imaging and surface microhardness studies. The results indicated the presence of equiaxed and homogeneous microstructures in both the base material and the automated welds, favoring isotropic behavior and tensile strength. In contrast, oriented columnar (or dendritic) microstructures, typical of manual welding, were identified, exhibiting higher local hardness but lower overall mechanical performance due to anisotropy and stress concentration in interdendritic regions. It was concluded that the main objective was achieved, since the conceptual design development and the construction of an automated prototype machine for TIG welding of tanks used in solar water heating systems were successfully carried out.