Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Microstructural characterization and evaluation of corrosion resistance in stainless steel applied in the pulp and paper industry
Submission Author:
Matheus Alves Lima , Buscando endereço... , Brazil
Co-Authors:
Matheus Alves Lima, Beatriz Garcia Bossatto , Davi Pereira Garcia, Felipe Malheiros, Henrique Bolonha, Warlen Alves Monfardini
Presenter: Matheus Alves Lima
doi://10.26678/ABCM.COBEM2023.COB2023-2175
Abstract
The occurrences of failures in industrial equipment result in higher maintenance costs. One of the main failure mechanisms is due to the effects of corrosion, caused by the performance of equipment in aggressive environments that compromise the integrity of the system. Recurrent situation in pulp and paper industries. The study of the failure mechanisms of a component present in an industry occurs through the analysis of the properties of the constituent materials, aiming at indicating traces that help to identify the possible causes of the problem. Thus, the objective of this work was to analyze stainless steel samples from components present in a paper and cellulose production industry, evaluating their main characteristics and their behavior to intergranular and pitting corrosion. All samples were characterized as to their microstructure through metallographic analysis using the Optical Microscope and electrolytic etching. The chemical composition was obtained through Optical Emission Spectroscopy. In order to simulate a recurrent thermal exposure in the work environment and to evaluate the resistance to corrosion, the samples underwent a sensitization treatment, treated at 675°C for 1 h and then quenched in water. Then, the electrochemical behavior was verified using the Anodic Potentiodynamic Polarization and Double Loop Electrochemical Potentiokinetic Reactivation (DL-EPR) tests. To verify the intergranular corrosion present in the samples after the DL-EPR tests, the surfaces were observed in the Scanning Electron Microscope (SEM). With the Dispersive Energy System (EDS), measurements were taken along the images obtained in the SEM to verify the chemical composition of the phases present in the microstructure of the samples. Through the results of the chemical analysis and metallographic tests, it was possible to classify the samples as stainless steels 316L and 304. In the electrochemical tests, the 316L steel samples showed better resistance to corrosion when compared to the 304 steel samples, which were mostly were sensitized after thermal treatment. The EDS was of fundamental importance to demonstrate the effect of sensitization through the difference in the content of chemical elements such as chromium and carbon in regions close to the grain boundaries in order to verify the existence of precipitation of chromium carbides. Thus, it was verified that using materials already degraded by the industrial process can lead to unexpected results compared to the literature, noting that the loss of their chemical properties directly influences the resistance to corrosion.
Keywords
Pulp and paper industry, corrosion, stainless steels, Metallography, Electrochemical tests
