TY - JOUR
T1 - Effect of solution annealing temperature on the localised corrosion behaviour of a modified super austenitic steel produced in an open-air atmosphere
AU - Ramírez, Jesús
AU - Berrio, E.
AU - Alvarado-Avila, María Isabel
AU - Field, D.
AU - Oñate, A.
AU - Sanhueza, J. P.
AU - Montoya, L. F.
AU - Meléndrez, M. F.
AU - Rojas, D.
N1 - Publisher Copyright:
© 2023 Elsevier B.V.
PY - 2023/4/15
Y1 - 2023/4/15
N2 - Two annealing heat treatments were investigated regarding localised corrosion behaviour on Nb and Mn-bearing super austenitic stainless steel. The material was designed based on physical metallurgical principles supported by Thermo-Calc modelling and was produced in an open-air atmosphere based on pre-sorted SS scrap plus ferroalloys elements. The production method aims for metal waste valorisation considering small foundries without an atmosphere-controlled process. Secondary phases at annealing temperatures were experimentally analysed by different microstructural characterisation methods and correlated by the Thermo-Calc modelling. In addition, electrochemical techniques and SKPFM were used to study the relationship between observed phases and localised corrosion performance. As the main results, a good correlation was observed between Thermo-Calc calculations and the microstructural characterisation. In particular, M23C6 carbides, σ phase, and Nb-MX were identified for the sample treated at 1120 °C, while for the sample treated at 1180 °C, σ phase and Nb-MX were identified, no M23C6 were detected. As regards localised corrosion behaviour, the M23C6 carbides and σ phase for sample 1120 °C generated Cr and Mo depletion zones and diminished the corrosion resistance in corrosive aqueous solutions. In the case of sample 1180 °C, the σ-phase with a smaller size and volume fraction than sample 1120 °C was observed, leading to a more uniform Cr and Mo distribution through the microstructure, obtaining high corrosion resistance and showing promising corrosion behaviour, similar to commercial SS 254smo considering its production in open-air.
AB - Two annealing heat treatments were investigated regarding localised corrosion behaviour on Nb and Mn-bearing super austenitic stainless steel. The material was designed based on physical metallurgical principles supported by Thermo-Calc modelling and was produced in an open-air atmosphere based on pre-sorted SS scrap plus ferroalloys elements. The production method aims for metal waste valorisation considering small foundries without an atmosphere-controlled process. Secondary phases at annealing temperatures were experimentally analysed by different microstructural characterisation methods and correlated by the Thermo-Calc modelling. In addition, electrochemical techniques and SKPFM were used to study the relationship between observed phases and localised corrosion performance. As the main results, a good correlation was observed between Thermo-Calc calculations and the microstructural characterisation. In particular, M23C6 carbides, σ phase, and Nb-MX were identified for the sample treated at 1120 °C, while for the sample treated at 1180 °C, σ phase and Nb-MX were identified, no M23C6 were detected. As regards localised corrosion behaviour, the M23C6 carbides and σ phase for sample 1120 °C generated Cr and Mo depletion zones and diminished the corrosion resistance in corrosive aqueous solutions. In the case of sample 1180 °C, the σ-phase with a smaller size and volume fraction than sample 1120 °C was observed, leading to a more uniform Cr and Mo distribution through the microstructure, obtaining high corrosion resistance and showing promising corrosion behaviour, similar to commercial SS 254smo considering its production in open-air.
KW - Cyclic polarisation curves
KW - DL-EPR
KW - SKPFM
KW - Sensitisation
KW - Solution annealing
KW - Super austenitic stainless steels
KW - Thermo-calc
UR - http://www.scopus.com/inward/record.url?scp=85148327588&partnerID=8YFLogxK
U2 - 10.1016/j.matchemphys.2023.127498
DO - 10.1016/j.matchemphys.2023.127498
M3 - Article
AN - SCOPUS:85148327588
SN - 0254-0584
VL - 299
JO - Materials Chemistry and Physics
JF - Materials Chemistry and Physics
M1 - 127498
ER -