Avaliação da Aplicabilidade da Manufatura Aditiva por Deposição a Arco (MADA) para Produção de Tubo de Aço Aplicado em Transporte de Cloro

Abstract

Basic sanitation is crucial for society and public health, and the choice of materials for chlorine conveyance presents challenges. This work explores the alternative manufacturing of a tube using the Wire Arc Additive Manufacturing (WAAM) process for transporting liquid chlorine, highlighting WAAM as a potential alternative. In the first method stage, preliminary fabrication aimed to optimize process parameters such as stability and heat dissipation in MIG/MAG welding and geometry, ensuring an appropriate shape without defects like porosities. The second stage compared the WAAM tube with the commercial SAE 1020 in terms of machining, processing data to evaluate machining force, and roughness was used to assess finishing. Hydrostatic tests were conducted with two pressures: 59 bar for 10 seconds and 15 bar for 3 hours. The tensile test used tubular samples and a plug to avoid internal deformations. The microstructure was revealed with 5% nital and analyzed using an optical microscope. In the third stage, the corrosion test between the WAAM tube and ASTM A106 grade B was conducted for 7 days in the laboratory and in service in a liquid chlorine plant, evaluating mass loss and corrosion rate. The main results showed that parameterization enabled the production of a high-quality piece with adequate geometry and no visible defects. The WAAM tube exhibited a machining force of 632.8 N at a feed rate of 0.15 mm/rev, comparable to the commercial tube. It showed no leaks in the hydrostatic test, confirming its tightness, and its mechanical properties are equivalent to grade B material, with a strength limit of 415 MPa. The microstructure revealed a predominance of ferrite in the lower regions and the presence of ferrite, pearlite, and other constituents in the upper regions. In the corrosion test, the WAAM tube achieved a rate of 0.70 mm/year, lower than the current tube's rate of 2.02 mm/year. In chlorine environments where strong acids predominantly form, the main corrosion mechanism was uniform, whereas in chlorides and weak acids, a mixed corrosion with pitting was observed. The study concluded that it is possible to manufacture a flanged tube using the WAAM process with equivalent mechanical properties and greater corrosion resistance than those currently used in the basic sanitation industry.