Fatigue Fracture Characteristics by Corrosion Degradation of 12Cr Alloy Steel

12Cr합금강의 부식열화에 의한 피로파괴 특성

  • Jo, Seon-Yeong (Korea Atomic Energy Research Institute) ;
  • Kim, Cheol-Han (Dept.of Mechanical Engineering, Sungkyunkwan University) ;
  • Bae, Dong-Ho (Dept.of Mechanical Engineering, Sungkyunkwan University)
  • 조선영 (한국 원자력 연구소) ;
  • 김철한 (성균관대학교 기계공학부) ;
  • 배동호 (성균관대학교 기계공학부)
  • Published : 2001.06.01


In order to investigate the fatigue fracture characteristics by corrosion degradation of 12Cr alloy steel, both the fatigue characteristics in air of them artificially degraded during long period and the corrosion fatigue characteristics were experimentally evaluated in various environments which were determined from electro-chemical polarization tests. And also, their fracture mechanisms were analyzed and compared, fractographyically. From their results, the fracture mechanical characteristics of it artificially degraded during long period in the distilled water, 3.5 wt.% NaCl solution and 12.7wt.%(1M) Na$_2$SO$_4$solution of 25, 60 and 90$\^{C}$ did not show distinguishable difference comparing with non-corroded one in regardless of temperature and degradation period. It means that degradation of the material by just surface corrosion does not remarkably affect to fatigue crack growth. On the other hand, the crack growth rates by corrosion fatigue increased due to activity increase of corrosive factors such as OH(sub)-,Cl(sup)- and SO$_4$(sup)- at the crack tip with temperature increase. Therefore, the crack growth rates by corrosion fatigue were more faster than that in air of the artificially degraded specimen due to the such difference of crack growth mechanism.


Corrosion Degradation;12Cr Alloy Steel;Fatigue;Corrosion Fatigue;Stress Intensity Factor Range;Crack Growth Rate;SEM Fractography


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