Per: julianna magalhães garcia (IME - INSTITUTO MILITAR DE ENGENHARIA), ANDREY DE MORAES BARCELOS CASANOVA (IME - INSTITUTO MILITAR DE ENGENHARIA), LUIZ PAULO MENDONÇA BRANDÃO (IME - INSTITUTO MILITAR DE ENGENHARIA)
Abstract:
Observations were made about the precipitation and microstructural changes of an AISI 310 austenitic steel welded through TIG process using a coated electrode - ER of steel 310. Innovating by the use of a similar ER 310 weld, replacing the Ni-based dissimilar weld , Inconel 625, widely used and studied for the welding of AISI 310 steels, however the latter, with the disadvantage of its higher cost. For the study, microhardness, ferritoscopy tests, evaluation by ThermoCalc and SEM-EDS were performed on the samples as received and after welding. As shown by the microhardness results, the weld material showed lower values than the base material, as well as the results of the ferritoscopy technique indicated a higher percentage of ferrite (magnetic phase) in the base metal. To investigate these changes, images as well as mappings were obtained through SEM / EDS. It was observed that there was a change in the microstructure of the base material, suggesting the inclusion of chromium carbide, thus causing the phenomenon of sensitization. Thereby, if applied, mainly the welded component at high temperatures, this precipitation would be a weakening factor of the material and limiting its service life, thus bringing an important discussion for this material, widely used in thermoelectric, nuclear and oil refineries.