INVESTIGATION ON THE EFFECT OF ANNEALING TEMPERATURE ON THE INTERGRANULAR CORROSION SUSCEPTIBILITY OF AISI 430 FERRITIC STAINLESS STEEL
Juliana Sarango de Souza1; Renato Altobelli Antunes1; Isaac Jamil Sayeg2
1 Universidade Federal do ABC; 2 Instituto de Geociências da USP
doi:10.20906/CPS/COB-2015-0562
Resumo
Ferritic stainless steels are replacing austenitic grades in automotive applications due to a more attractive combination of material performance and cost. Welding operations are commonly employed as part of the manufacturing schedule of automotive parts. Depending on the time and temperature of thermal cycles to which the material is exposed, sensitization can take place due to precipitation of chromium carbides at grain boundaries, thus leading to intergranular corrosion. The aim of the present study was to investigate the intergranular corrosion susceptibility of the AISI 409 ferritic stainless steel submitted to different annealing conditions. The degree of sensitization (DOS) was determined using the double-loop electrochemical potentiokinetic reactivation (DL-EPR) method. Visual analysis was also undertaken by optical microscopy based on ASTM 763 practice W. The precipitates within the ferrite matrix were identified by scanning electron microscopy (SEM). The results showed that the material became more susceptible to intergranular corrosion after annealing at 600C, 650C and 900C. DL-EPR results were in agreement with the microstructural features observed after the tests based on practice W of ASTM 763.
Palavras-chave: AISI 409 stainless steel; intergranular corrosion; DL-EPR