TY - JOUR

T1 - Depletion zones and intergranular corrosion of superaustenitic stainless steel Alloy 926

AU - Mori, Gregor Karl

AU - Prohaska, Manuel

AU - Lackner, Roland

AU - Rokosz, K.

AU - Albu, Mihaela

AU - Kothleitner, Gerald

PY - 2017/3/1

Y1 - 2017/3/1

N2 - Superaustenitic stainless steel Alloy 926 was evaluated after different isothermal annealing and thermomechanical heat treatments. The impact of two different quenching and tempering processes on sensitization was determined. Since Alloy 926 contains large amounts of molybdenum and chromium, precipitation of various intermetallic phases is strongly favored. Based on SEM and EF-TEM, it was found that the size as well as the extent of elemental depletion zones is in good agreement with the degree of sensitization (DOS), independently of the applied corrosion test. Elemental depletion zones of two isothermally annealed conditions were obtained quantitatively and related to those of thermo-mechanically rolled samples. Comparison of both annealed conditions revealed the different operating principles of Streicher test and DL-EPR-test. In consequence, morphology, distribution, and chemical composition of precipitates have a considerable impact on corrosion test results. Different microstructural parameters and their relevance on prediction of corrosion properties are pointed out and discussed accurately.

AB - Superaustenitic stainless steel Alloy 926 was evaluated after different isothermal annealing and thermomechanical heat treatments. The impact of two different quenching and tempering processes on sensitization was determined. Since Alloy 926 contains large amounts of molybdenum and chromium, precipitation of various intermetallic phases is strongly favored. Based on SEM and EF-TEM, it was found that the size as well as the extent of elemental depletion zones is in good agreement with the degree of sensitization (DOS), independently of the applied corrosion test. Elemental depletion zones of two isothermally annealed conditions were obtained quantitatively and related to those of thermo-mechanically rolled samples. Comparison of both annealed conditions revealed the different operating principles of Streicher test and DL-EPR-test. In consequence, morphology, distribution, and chemical composition of precipitates have a considerable impact on corrosion test results. Different microstructural parameters and their relevance on prediction of corrosion properties are pointed out and discussed accurately.

KW - Alloy 926

KW - depletion zone

KW - EPR test

KW - intergranular corrosion

KW - sensitization

UR - http://www.scopus.com/inward/record.url?scp=85000819068&partnerID=8YFLogxK

U2 - 10.1002/maco.201609152

DO - 10.1002/maco.201609152

M3 - Article

AN - SCOPUS:85000819068

VL - 68.2017

SP - 284

EP - 294

JO - Materials and Corrosion

JF - Materials and Corrosion

SN - 0947-5117

IS - 3

ER -