Corrosion Science and Technology

The Corrosion Science Society of Korea (한국부식방식학회)
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Effect of Induction Heat Bending Process on the Corrosion Properties of 316 Stainless Steel Pipes for Nuclear Power Plant

원자력발전소용 316 스테인리스강 배관의 부식특성에 미치는 유도가열벤딩공정의 영향

  • Shin, Mincheol (Materials Research Center for Clean and Energy Technology, School of Materials Science and Engineering Materials, Andong National University) ;
  • Kim, Young Sik (Materials Research Center for Clean and Energy Technology, School of Materials Science and Engineering Materials, Andong National University) ;
  • Kim, Kyungsu (KEPCO E&C) ;
  • Chang, Hyunyoung (KEPCO E&C) ;
  • Park, Heungbae (KEPCO E&C) ;
  • Sung, Giho (Sungil SIM Co. Ltd.)
  • 신민철 (안동대학교 신소재공학부 청정에너지소재기술연구센터) ;
  • 김영식 (안동대학교 신소재공학부 청정에너지소재기술연구센터) ;
  • 김경수 (한국전력기술주식회사) ;
  • 장현영 (한국전력기술주식회사) ;
  • 박흥배 (한국전력기술주식회사) ;
  • 성기호 (성일SIM(주))
  • Received : 2014.05.29
  • Accepted : 2014.06.23
  • Published : 2014.06.30
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Abstract

Recently, the application of bending products has been increased since the industries such as automobile, aerospace, ships, and plants greatly need the usage of pipes. For facility fabrication, bending process is one of key technologies for pipings. Induction heat bending process is composed of bending deformation by repeated local heat and cooling. Because of local heating and compressive strain, detrimental phases may be precipitated and microstructural change can be induced. This work focused on the effect of induction heat bending process on the properties of ASME SA312 TP316 stainless steel. Evaluation was done on the base metal and the bended areas before and after heat treatment. Microstructure analysis, intergranular corrosion test including Huey test, double loop electropotentiokinetic reactivation test, oxalic acid etch test, and anodic polarization test were performed. On the base of microstructural analysis, grain boundaries in bended extrados area were zagged by bending process, but there were no precipitates in grain and grain boundary and the intergranular corrosion rate was similar to that of base metal. However, pitting potentials of bended area were lower than that of the base metal and zagged boundaries was one of the pitting initiation sites. By re-annealing treatment, grain boundary was recovered and pitting potential was similar to that of the base metal.

Keywords

References

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