Transactions of Materials Processing (소성∙가공)

The Korean Society for Technology of Plasticity and materials processing (한국소성∙가공학회)
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Effects of Rare Earth Metals Addition and Aging Treatment on the Corrosion Resistance and Mechanical Properties of Super Duplex Stainless Steels

  • 박용수 (Departmant of Metallurgical Engineering) ;
  • 김순태 (Departmant of Metallurgical Engineering) ;
  • 이인성 (National Research Laboratory, Departmant of Metallurgical Engineering) ;
  • 송치복 (National Research Laboratory, Departmant of Metallurgical Engineering)
  • Published : 1999.06.01

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Abstract

Effects of rare earth metals addition and aging treatment on corrosion resistance and mechanical properties of super duplex stainless steels were investigated using optical/SEM/TEM metallographic examination, an X-ray diffraction test, a potentiodynamic anodic polarization test and a tensile test. The performance of the experimental alloy with 0.32% REM addition was compared with commercial super duplex stainless steel such as SAF 2507 when they were exposed to solution annealing heat treatment and aging treatment. The corrosion resistance in CF environments and mechanical properties of the experimental alloy were found superior to those of the commercial duplex stainless steel. The REM with larger atomic radii than those of Cr, Mo and W may fill vacancies inside the matrix and around the grain boundaries, retarding formation of harmful intermetallic σ and χ phases. In addition, fine REM oxides/oxy-sulfides (1-3㎛) seemed to enhance the retardation effects. With REM additions, strength and ductility increased due to the phase and grain refinement caused by fine REM oxides and oxy-sulfides.

Keywords

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