Investigação da erosividade de cinzas oriundas de combustível derivado de resíduo em aço AISI 310 e AISI 321 tratados termicamicamente

Abstract

Society currently faces two challenges: developing renewable and economically viable energy sources; and seek a sustainable destination for waste. The production of energy from fuel derived from waste can solve part of both problems. However, one must study the tribological system involved for this technology to make its increasingly profitable. Thus, some factors were investigated and resistance to erosive wear was compared under conditions close to those found in cyclones, by means of erosion tests on austenitic stainless steels, grades AISI 310 and AISI 321, after heat treatments, at air jet erosimeter standardized according to ASTM G76-18. The treatments were solubilization and aging in grades 310, and solubilization and stabilization in grades 321. The hardness, microstructure and surface roughness were evaluated before treatments. The test conditions were: at room temperature, at 30 g / min of particle flow for 10 minutes, at 30 ° and 90 ° of impact angle, with 50 µm alumina and ash (70% from 150 to 425 µm) from a thermochemical reactor for the production of fuel derived from waste. Ash erosivity was evaluated by testing samples of stainless steel 304 at 30 m/s and 70 m/s, which resulted in erosion rates close to those found with alumina in the standard. The analysis under scanning electron microscope found ductile mechanisms, such as microscracking and microcutting, with a predominance of the first when tested with ash and the second when tested with alumina. Wear rates were higher than ash in most conditions. When tested with alumina, it wears more at 30 °, however, when tested with ash, it wears more at 90 °. An increase in resistance against ash erosion at 90º of grade 310 was observed when aged, and an increase in resistance against erosion of alumina at 30º of grade 321 when stabilized. The micrographs revealed that the lower resistance of the steels treated by solubilization occurred due to the growth of grains.