Journal of Welding and Joining

The Korean Welding and Joining Society (대한용접접합학회)
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Effect of Post-Weld Heat Treatment on the Mechanical Properties and Microstructure of P-No. 1 Carbon Steels

P-No. 1 탄소강의 기계적 특성과 미세조직에 미치는 용접후열처리의 영향

  • Lee, Seung-Gun (Joining Technology Department, Korea Institute of Materials Science) ;
  • Kang, Yongjoon (Joining Technology Department, Korea Institute of Materials Science) ;
  • Kim, Gi-Dong (Joining Technology Department, Korea Institute of Materials Science) ;
  • Kang, Sung-Sik (Dept. of Nuclear Safety Research, Korea Institute of Nuclear Safety)
  • 이승건 (한국기계연구원 부설 재료연구소 접합기술연구실) ;
  • 강용준 (한국기계연구원 부설 재료연구소 접합기술연구실) ;
  • 김기동 (한국기계연구원 부설 재료연구소 접합기술연구실) ;
  • 강성식 (한국원자력안전기술원 원자력안전연구실)
  • Received : 2017.02.01
  • Accepted : 2017.02.24
  • Published : 2017.02.28
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Abstract

This study aims to investigate the suitability of requirement for post-weld heat treatment(PWHT) temperature when different P-No. materials are welded, which is defined by ASME Sec. III Code. For SA-516 Gr. 60 and SA-106 Gr. B carbon steels that are typical P-No. 1 material, simulated heat treatment were conducted for 8 h at $610^{\circ}C$, $650^{\circ}C$, $690^{\circ}C$, and $730^{\circ}C$, last two temperature falls in the temperature of PWHT for P-No. 5A low-alloy steels. Tensile and Charpy impact tests were performed for the heat-treated specimens, and then microstructure was analyzed by optical microscopy and scanning electron microscopy with energy-dispersive spectrometry. The Charpy impact properties deteriorated significantly mainly due to a large amount of cementite precipitation when the temperature of simulated heat treatment was $730^{\circ}C$. Therefore, when dissimilar metal welding is carried out for P-No. 1 carbon steel and different P-No. low alloy steel, the PWHT temperature should be carefully selected to avoid significant deterioration of impact properties for P-No. 1 carbon steel.

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References

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