Caracterização mecânica e metalográfica de juntas soldadas a laser para aplicação em equipamento agrícola

Abstract

Laser welding has been increasingly used as joining process in the industrial market due to its advantages, such as joint quality and mass reduction. This welding process has high potential for applications in agricultural equipment due to the nature of the work and its ability to minimize soil compaction. In this study, the influence of three welding parameters (base materials, laser power and welding speed) on the values of maximum hardness, depth of penetration, bead width, end width and gaps were investigated. For this purpose, an experimental design with three factors was proposed, where the power varied from 5000 W to 6000 W and the speeds ranged from 53 mm/min to 63 mm/min. Three types of materials were evaluated, including two Ultra High Strength Steels and one Cold-Formed High Strength Steel. The ANOVA analysis showed that in the chosen range none of the input factors significantly influenced the hardness variation in the welded region or the gaps between the sheets. However, regarding penetration depth and width of the welded region at the plate intersection, the results indicated that only power had a statistically significant influence. Furthermore, the results suggested that the materials had a statistical influence on the measured values of the bead width. Considering the application of these assemblies in agricultural equipment subjected to repetitive loads, the hardness results indicated that the welded joint with higher power (6000 W) and higher speed (63 mm/min) would be more fatigue-resistant and consequently have a longer service life.