Estudo de processos de soldagem e proposta de melhoria de uniões soldadas críticas de uma caçamba escavadeira com foco na prevenção da fadiga em serviço

Abstract

With the modernization of steel, excavator buckets for mining had a significant reduction in mass, which promoted the reduction of polluting gas emissions from the equipment where these implements are installed. However, these materials are supplied on the market heat treated, requiring certain care before, during and after welding, where if all parameters and operating techniques for manufacturing the implement are not correctly evaluated and selected, it may not perform from 2,000 to 3,000 operating hours contractually required by customers. To mitigate the consequences of the welding process, such as residual stresses, this study aimed to understand the welding processes and parameters that are most suitable for the construction of implements, evaluating both the productive and metallurgical points of view, as well as seeking to select materials that, in addition to having a low carbon equivalent, must present good resistance to lamellar decohesion due to the large volume of welding found in this equipment, proposing to present improvements in the design to mitigate fatigue. The study indicated that despite the impact caused by welding on materials, the theory that addresses fatigue emphasizes that the shape of the joint is the most preponderant factor for the occurrence of the mechanical phenomenon, but that the sum of several factors intrinsic to the construction of the implement, cannot be neglected to postpone fatigue.